Primality proof for n = 38933:

Take b = 2.

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

9733 is prime.
b^((n-1)/9733)-1 mod n = 15, which is a unit, inverse 33742.

(9733) divides n-1.

(9733)^2 > n.

n is prime by Pocklington's theorem.