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.