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.