Primality proof for n = 16699:
Take b = 2.
b^(n-1) mod n = 1.
23 is prime.
b^((n-1)/23)-1 mod n = 8016, which is a unit, inverse 6960.
11 is prime.
b^((n-1)/11)-1 mod n = 1560, which is a unit, inverse 12642.
(11^2 * 23) divides n-1.
(11^2 * 23)^2 > n.
n is prime by Pocklington's theorem.