Primality proof for n = 8312956054562778877481:

Take b = 2.

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

1019532643 is prime.
b^((n-1)/1019532643)-1 mod n = 1622789414516127142474, which is a unit, inverse 7349153878600622169760.

208393 is prime.
b^((n-1)/208393)-1 mod n = 2460496464207392644677, which is a unit, inverse 495907208976900334963.

(208393 * 1019532643) divides n-1.

(208393 * 1019532643)^2 > n.

n is prime by Pocklington's theorem.