REVERSAL-ADDITION PALINDROME TEST ON 10701592943 Reverse and Add Process: 1. Pick a number. 2. Reverse its digits and add this value to the original number. 3. If this is not a palindrome, go back to step 2 and repeat. Let's view this Reverse and Add sequence starting with 10701592943: 10701592943 + 34929510701 step 1: 45631103644 + 44630113654 step 2: 90261217298 + 89271216209 step 3: 179532433507 + 705334235971 step 4: 884866669478 + 874966668488 step 5: 1759833337966 + 6697333389571 step 6: 8457166727537 + 7357276617548 step 7: 15814443345085 + 58054334441851 step 8: 73868777786936 + 63968777786837 step 9: 137837555573773 + 377375555738731 step 10: 515213111312504 + 405213111312515 step 11: 920426222625019 + 910526222624029 step 12: 1830952445249048 + 8409425442590381 step 13: 10240377887839429 + 92493878877304201 step 14: 102734256765143630 + 036341567652437201 step 15: 139075824417580831 + 138085714428570931 step 16: 277161538846151762 + 267151648835161772 step 17: 544313187681313534 + 435313186781313445 step 18: 979626374462626979 + 979626264473626979 step 19: 1959252638936253958 + 8593526398362529591 step 20: 10552779037298783549 + 94538789273097725501 step 21: 105091568310396509050 + 050905693013865190501 step 22: 155997261324261699551 + 155996162423162799551 step 23: 311993423747424499102 + 201994424747324399113 step 24: 513987848494748898215 + 512898847494848789315 step 25: 1026886695989597687530 + 0357867959895966886201 step 26: 1384754655885564573731 + 1373754655885564574831 step 27: 2758509311771129148562 + 2658419211771139058572 step 28: 5416928523542268207134 + 4317028622453258296145 step 29: 9733957145995526503279 + 9723056255995417593379 step 30: 19457013401990944096658 + 85669044909910431075491 step 31: 105126058311901375172149 + 941271573109113850621501 step 32: 1046397631421015225793650 + 0563975225101241367936401 step 33: 1610372856522256593730051 + 1500373956522256582730161 step 34: 3110746813044513176460212 + 2120646713154403186470113 step 35: 5231393526198916362930325 + 5230392636198916253931325 step 36: 10461786162397832616861650 + 05616861623879326168716401 step 37: 16078647786277158785578051 + 15087558785177268774687061 step 38: 31166206571454427560265112 + 21156206572445417560266113 step 39: 52322413143899845120531225 + 52213502154899834131422325 step 40: 104535915298799679251953550 + 055359152976997892519535401 step 41: 159895068275797571771488951 + 159884177175797572860598951 step 42: 319779245451595144632087902 + 209780236441595154542977913 step 43: 529559481893190299175065815 + 518560571992091398184955925 step 44: 1048120053885281697360021740 + 0471200637961825883500218401 step 45: 1519320691847107580860240141 + 1410420680857017481960239151 step 46: 2929741372704125062820479292 + 2929740282605214072731479292 step 47: 5859481655309339135551958584 + 4858591555319339035561849585 step 48: 10718073210628678171113808169 + 96180831117187682601237081701 step 49: 106898904327816360772350889870 + 078988053277063618723409898601 step 50: 185886957604879979495760788471 + 174887067594979978406759688581 step 51: 360774025199859957902520477052 + 250774025209759958991520477063 step 52: 611548050409619916894040954115 + 511459040498619916904050845116 step 53: 1123007090908239833798091799231 + 1329971908973389328090907003211 step 54: 2452978999881629161888998802442 + 2442088998881619261889998792542 step 55: 4895067998763248423778997594984 + 4894957998773248423678997605984 step 56: 9790025997536496847457995200968 + 8690025997547486946357995200979 step 57: 18480051995083983793815990401947 + 74910409951839738938059915008481 step 58: 93390461946923722731875905410428 + 82401450957813722732964916409339 step 59: 175791912904737445464840821819767 + 767918128048464544737409219197571 step 60: 943710040953201990202250041017338 + 833710140052202099102359040017349 step 61: 1777420181005404089304609081034687 + 7864301809064039804045001810247771 step 62: 9641721990069443893349610891282458 + 8542821980169433983449600991271469 step 63: 18184543970238877876799211882553927 + 72935528811299767877883207934548181 step 64: 91120072781538645754682419817102108 + 80120171891428645754683518727002119 step 65: 171240244672967291509365938544104227 + 722401445839563905192769276442042171 step 66: 893641690512531196702135214986146398 + 893641689412531207691135215096146398 step 67: 1787283379925062404393270430082292796 + 6972922800340723934042605299733827871 step 68: 8760206180265786338435875729816120667 + 7660216189275785348336875620816020678 step 69: 16420422369541571686772751350632141345 + 54314123605315727768617514596322402461 step 70: 70734545974857299455390265946954543806 + 60834545964956209355499275847954543707 step 71: 131569091939813508810889541794909087513 + 315780909497145988018805318939190965131 step 72: 447350001436959496829694860734100052644 + 446250001437068496928694959634100053744 step 73: 893600002874027993758389820368200106388 + 883601002863028983857399720478200006398 step 74: 1777201005737056977615789540846400112786 + 6872110046480459875167796507375001027771 step 75: 8649311052217516852783586048221401140557 + 7550411041228406853872586157122501139468 step 76: 16199722093445923706656172205343902280025 + 52008220934350227165660732954439022799161 step 77: 68207943027796150872316905159782925079186 + 68197052928795150961327805169772034970286 step 78: 136404995956591301833644710329554960049472 + 274940069455923017446338103195659599404631 step 79: 411345065412514319279982813525214559454103 + 301454955412525318289972913415214560543114 step 80: 712800020825039637569955726940429119997217 + 712799911924049627559965736930528020008217 step 81: 1425599932749089265129921463870957140005434 + 4345000417590783641299215629809472399955241 step 82: 5770600350339872906429137093680429539960675 + 5760699359240863907319246092789330530060775 step 83: 11531299709580736813748383186469760070021450 + 05412007006796468138384731863708590799213511 step 84: 16943306716377204952133115050178350869234961 + 16943296805387105051133125940277361760334961 step 85: 33886603521764310003266240990455712629569922 + 22996592621755409904266230001346712530668833 step 86: 56883196143519719907532470991802425160238755 + 55783206152420819907423570991791534169138865 step 87: 112666402295940539814956041983593959329377620 + 026773923959395389140659418935049592204666211 step 88: 139440326255335928955615460918643551534043831 + 138340435155346819064516559829533552623044931 step 89: 277780761410682748020132020748177104157088762 + 267880751401771847020231020847286014167087772 step 90: 545661512812454595040363041595463118324176534 + 435671423811364595140363040595454218215166545 step 91: 981332936623819190180726082190917336539343079 + 970343935633719091280627081091918326639233189 step 92: 1951676872257538281461353163282835663178576268 + 8626758713665382823613531641828357522786761591 step 93: 10578435585922921105074884805111193185965337859 + 95873356958139111150848847050112922958553487501 step 94: 106451792544062032255923731855224116144518825360 + 063528815441611422558137329552230260445297154601 step 95: 169980607985673454814061061407454376589815979961 + 169979518985673454704160160418454376589706089961 step 96: 339960126971346909518221221825908753179522069922 + 229960225971357809528122122815909643179621069933 step 97: 569920352942704719046343344641818396359143139855 + 558931341953693818146443343640917407249253029965 step 98: 1128851694896398537192786688282735803608396169820 + 0289616938063085372828866872917358936984961588211 step 99: 1418468632959483910021653561200094740593357758031 + 1308577533950474900021653561200193849592368648141 step 100: 2727046166909958810043307122400288590185726406172 + 2716046275810958820042217033400188599096616407272 step 101: 5443092442720917630085524155800477189282342813444 + 4443182432829817740085514255800367190272442903445 step 102: 9886274875550735370171038411600844379554785716889 + 9886175874559734480061148301710735370555784726889 step 103: 19772450750110469850232186713311579750110570443778 + 87734407501105797511331768123205896401105705427791 step 104: 107506858251216267361563954836517476151216275871569 + 965178572612151674715638459365163762612152858605701 step 105: 1072685430863367942077202414201681238763369134477270 + 0727744319633678321861024142027702497633680345862701 step 106: 1800429750497046263938226556229383736397049480339971 + 1799330849407936373839226556228393626407940579240081 step 107: 3599760599904982637777453112457777362804990059580052 + 2500859500994082637777542113547777362894099950679953 step 108: 6100620100899065275554995226005554725699090010260005 + 5000620100909965274555006225994555725609980010260016 step 109: 11101240201809030550110001452000110451309070020520021 + 12002502007090315401100025410001105503090810204210111 step 110: 23103742208899345951210026862001215954399880224730132 10701592943 takes 110 iterations / steps to resolve into a 53 digit palindrome. REVERSAL-ADDITION PALINDROME RECORDS Most Delayed Palindromic Number for each digit length (Only iteration counts for which no smaller records exist are considered. My program records only the smallest number that resolves for each distinct iteration count. For example, there are 18-digit numbers that resolve in 232 iterations, higher than the 228 iteration record shown for 18-digit numbers, but they were not recorded, as a smaller [17-digit] number already holds the record for 232 iterations.) Digits Number Result 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 89 187 1,297 10,911 150,296 9,008,299 10,309,988 140,669,390 1,005,499,526 10,087,799,570 100,001,987,765 1,600,005,969,190 14,104,229,999,995 100,120,849,299,260 1,030,020,097,997,900 10,442,000,392,399,960 170,500,000,303,619,996 1,186,060,307,891,929,990 solves in 24 iterations. solves in 23 iterations. solves in 21 iterations. solves in 55 iterations. solves in 64 iterations. solves in 96 iterations. solves in 95 iterations. solves in 98 iterations. solves in 109 iterations. solves in 149 iterations. solves in 143 iterations. solves in 188 iterations. solves in 182 iterations. solves in 201 iterations. solves in 197 iterations. solves in 236 iterations. solves in 228 iterations. solves in 261 iterations - World Record! [View all records] This reverse and add program was created by Jason Doucette. Please visit my Palindromes and World Records page. You have permission to use the data from this webpage (with due credit). A link to my website is much appreciated. Thank you. (This program has been run 2,542,579 times since Saturday, March 9th, 2002.)