This number is a prime.
If a number can be written as 2a^2+1 or as 3b^3+1, it must be of the form 648k^6+1. This is prime for k = 3, 4 and 5 [Hartley]
If a number can be written as 2a^2+1 or as 3b^3+1, it must be of the form 648k^6+1. This is prime for k = 3, 4 and 5 [Hartley]