Palindrome.

PFGW Version 1.2.0 for Windows [FFT v23.8]

Primality testing (9*10^(7591+7)+6621266)*10^(7591+1)+9
[N-1/N+1, Brillhart-Lehmer-Selfridge]
Running N-1 test using base 3
Running N-1 test using base 7
Running N+1 test using discriminant 13, base 1+sqrt(13)
Running N+1 test using discriminant 13, base 4+sqrt(13)
(9*10^(7591+7)+6621266)*10^(7591+1)+9 is Fermat and Lucas PRP!

To be completed...