Primality proof for n = 12227:
Take b = 2.
b^(n-1) mod n = 1.
6113 is prime. b^((n-1)/6113)-1 mod n = 3, which is a unit, inverse 4076.
(6113) divides n-1.
(6113)^2 > n.
n is prime by Pocklington's theorem.