121499449

This number is a prime.

+ The largest prime factor of any 28-digit repdigit. Note that 28 is perfect. [Bowser]

+ The largest prime (emirp) factor of 10^14+1. [Loungrides]

+ The largest prime factor, (it is also emirp), of any number formed by repeating seven times any 4-digit number, (prime or composite). [Loungrides]

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