Primality proof for n = 33997:

Take b = 2.

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

2833 is prime.
b^((n-1)/2833)-1 mod n = 4095, which is a unit, inverse 11598.

(2833) divides n-1.

(2833)^2 > n.

n is prime by Pocklington's theorem.