Take b = 2.

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

829 is prime.

b^((n-1)/829)-1 mod n = 20125837, which is a unit, inverse 11031582.

73 is prime.

b^((n-1)/73)-1 mod n = 1326340, which is a unit, inverse 15704421.

(73 * 829) divides n-1.

(73 * 829)^2 > n.

n is prime by Pocklington's theorem.