21462...98751 (43009-digits)

This number is a prime.

+ 12291*2^142857-1 is prime. Note that 12291 written in base-4 is palindromic (3000003). Also, if you sum the factorials of the digits of 12291*2^142857-1 you get the prime 1767235343. [Earls]

Printed from the PrimePages <primes.utm.edu> © G. L. Honaker and Chris K. Caldwell