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.