This number is a prime.
The third known prime number of the form 2^(p-1)*(2^p-1)+1, where 2^p-1 is a Mersenne prime. Such numbers are
called right perfect primes. The first and second ones are 7 and 29. [Rivera]
Printed from the PrimePages <primes.utm.edu> © G. L. Honaker and Chris K. Caldwell