Primality proof for n = 752881:
Take b = 2.
b^(n-1) mod n = 1.
3137 is prime. b^((n-1)/3137)-1 mod n = 734443, which is a unit, inverse 156840.
(3137) divides n-1.
(3137)^2 > n.
n is prime by Pocklington's theorem.