Primality proof for n = 165703:
Take b = 2.
b^(n-1) mod n = 1.
27617 is prime. b^((n-1)/27617)-1 mod n = 63, which is a unit, inverse 76276.
(27617) divides n-1.
(27617)^2 > n.
n is prime by Pocklington's theorem.