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(372215 spells 'SIZZLE' when turned upside down on a calculator.)

PFGW Version 1.2.0 for Windows [FFT v23.8]

Primality testing 10^15375+372215001
[N-1/N+1, Brillhart-Lehmer-Selfridge]
Running N-1 test using base 7
Running N+1 test using discriminant 23, base 3+sqrt(23)
10^15375+372215001 is Fermat and Lucas PRP!

To be completed...