Primality proof for n = 2458171673961827:
Take b = 2.
b^(n-1) mod n = 1.
3270593687 is prime.
b^((n-1)/3270593687)-1 mod n = 1263111296724624, which is a unit, inverse 1565665397189453.
(3270593687) divides n-1.
(3270593687)^2 > n.
n is prime by Pocklington's theorem.