REVERSAL-ADDITION PALINDROME TEST ON 108933

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 108933:
108933
+ 339801
step 1: 448734
+ 437844
step 2: 886578
+ 875688
step 3: 1762266
+ 6622671
step 4: 8384937
+ 7394838
step 5: 15779775
+ 57797751
step 6: 73577526
+ 62577537
step 7: 136155063
+ 360551631
step 8: 496706694
+ 496607694
step 9: 993314388
+ 883413399
step 10: 1876727787
+ 7877276781
step 11: 9754004568
+ 8654004579
step 12: 18408009147
+ 74190080481
step 13: 92598089628
+ 82698089529
step 14: 175296179157
+ 751971692571
step 15: 927267871728
+ 827178762729
step 16: 1754446634457
+ 7544366444571
step 17: 9298813079028
+ 8209703188929
step 18: 17508516267957
+ 75976261580571
step 19: 93484777848528
+ 82584877748439
step 20: 176069655596967
+ 769695556960671
step 21: 945765212557638
+ 836755212567549
step 22: 1782520425125187
+ 7815215240252871
step 23: 9597735665378058
+ 8508735665377959
step 24: 18106471330756017
+ 71065703317460181
step 25: 89172174648216198
+ 89161284647127198
step 26: 178333459295343396
+ 693343592954333871
step 27: 871677052249677267
+ 762776942250776178
step 28: 1634453994500453445
+ 5443540054993544361
step 29: 7077994049493997806
+ 6087993949404997707
step 30: 13165987998898995513
+ 31559989889978956131
step 31: 44725977888877951644
+ 44615977888877952744
step 32: 89341955777755904388
+ 88340955777755914398
step 33: 177682911555511818786
+ 687818115555119286771
step 34: 865501027110631105557
+ 755501136011720105568
step 35: 1621002163122351211125
+ 5211121532213612001261
step 36: 6832123695335963212386
108933 takes 36 iterations / steps to resolve into a 22 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.)

DigitsNumberResult
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 1,768,474 times since Saturday, March 9th, 2002.)