Primality proof for n = 207941:

Take b = 2.

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

281 is prime.
b^((n-1)/281)-1 mod n = 206196, which is a unit, inverse 50168.

37 is prime.
b^((n-1)/37)-1 mod n = 38772, which is a unit, inverse 185775.

(37 * 281) divides n-1.

(37 * 281)^2 > n.

n is prime by Pocklington's theorem.