Primality proof for n = 2207:

Take b = 2.

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

1103 is prime.
b^((n-1)/1103)-1 mod n = 3, which is a unit, inverse 736.

(1103) divides n-1.

(1103)^2 > n.

n is prime by Pocklington's theorem.