Primality proof for n = 28597:

Take b = 2.

b^(n-1) mod n = 1.

2383 is prime.
b^((n-1)/2383)-1 mod n = 4095, which is a unit, inverse 3785.

(2383) divides n-1.

(2383)^2 > n.

n is prime by Pocklington's theorem.