Primality proof for n = 426632512014427833817:

Take b = 2.

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

23314383343543 is prime.
b^((n-1)/23314383343543)-1 mod n = 53960818949260564655, which is a unit, inverse 62814440624553491211.

(23314383343543) divides n-1.

(23314383343543)^2 > n.

n is prime by Pocklington's theorem.