Primality proof for n = 5975923:
Take b = 2.
b^(n-1) mod n = 1.
995987 is prime. b^((n-1)/995987)-1 mod n = 63, which is a unit, inverse 3604525.
(995987) divides n-1.
(995987)^2 > n.
n is prime by Pocklington's theorem.