Primality proof for n = 37447:
Take b = 2.
b^(n-1) mod n = 1.
79 is prime. b^((n-1)/79)-1 mod n = 17193, which is a unit, inverse 26082.
(79^2) divides n-1.
(79^2)^2 > n.
n is prime by Pocklington's theorem.