The next palindromic number after 1991 is 2002. A palindromic number reads the same forwards and backwards. In this case, 2002 reads the same whether you read it left to right or right to left.
The next palindromic years are going to be 2112 and 2222. There is a 100 year difference between the two.
52925 53035
36063 Then... 36163 36263
69996 70007 70107
A palindrome reads the same both ways. The last palindromic year was 2002. the next palindromic year is 2112. However, the next palindromic date dd/mm/yyyy is 01/02/2010 (01022010)
6446
206602
The next palindromic number after 1991 is 2002. A palindromic number reads the same forwards and backwards. In this case, 2002 reads the same whether you read it left to right or right to left.
2112 and 2222
The next palindromic years are going to be 2112 and 2222. There is a 100 year difference between the two.
52925 53035
36063 Then... 36163 36263
69996 70007 70107
11.11 Although if you restrict yourself to integers, the answer is 22
1661 is a palindromic number.
You call it a palindromic sentence. If it isn't a sentence it is a palindromic phrase or palindromic sequence.