Primality proof for n = 7207:
Take b = 2.
b^(n-1) mod n = 1.
1201 is prime. b^((n-1)/1201)-1 mod n = 63, which is a unit, inverse 572.
(1201) divides n-1.
(1201)^2 > n.
n is prime by Pocklington's theorem.