Primality proof for n = 159793:

Take b = 2.

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

3329 is prime.
b^((n-1)/3329)-1 mod n = 141642, which is a unit, inverse 27379.

(3329) divides n-1.

(3329)^2 > n.

n is prime by Pocklington's theorem.