Primality proof for n = 577:
Take b = 5.
b^(n-1) mod n = 1.
3 is prime.
b^((n-1)/3)-1 mod n = 362, which is a unit, inverse 263.
2 is prime.
b^((n-1)/2)-1 mod n = 575, which is a unit, inverse 288.
(2^6 * 3^2) divides n-1.
(2^6 * 3^2)^2 > n.
n is prime by Pocklington's theorem.