Primality proof for n = 12397338596863679689524759770405177749801411:

Take b = 2.

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

413244619895455989650825325680172591660047 is prime.
b^((n-1)/413244619895455989650825325680172591660047)-1 mod n = 1073741823, which is a unit, inverse 302965702597983423679073862837973295262978.

(413244619895455989650825325680172591660047) divides n-1.

(413244619895455989650825325680172591660047)^2 > n.

n is prime by Pocklington's theorem.