Primality proof for n = 84178317913:
Take b = 2.
b^(n-1) mod n = 1.
3415219 is prime. b^((n-1)/3415219)-1 mod n = 45664754278, which is a unit, inverse 59930863590.
(3415219) divides n-1.
(3415219)^2 > n.
n is prime by Pocklington's theorem.