This number is a prime.
The smallest prime which may be written as 2a^2-1 and as 3b^3-1 and as 5c^5-1 and also as 7d^7-1 [Hartley]
The smallest prime which may be written as 2a^2-1 and as 3b^3-1 and as 5c^5-1 and also as 7d^7-1 [Hartley]