The number 1721352171 is close to having the same digits as the 7th row of Pascal's triangle -- only one of the 35's is missing.

PFGW Version 1.2.0 for Windows [FFT v23.8]

Primality testing 10^19417+1721352171 [N-1/N+1, Brillhart-Lehmer-Selfridge]
Running N-1 test using base 2
Running N-1 test using base 3
Running N-1 test using base 19
Running N+1 test using discriminant 31, base 1+sqrt(31)
10^19417+1721352171 is Fermat and Lucas PRP!

To be completed...