Primality proof for n = 10434257:

Take b = 2.

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

13309 is prime.
b^((n-1)/13309)-1 mod n = 8271012, which is a unit, inverse 4898857.

(13309) divides n-1.

(13309)^2 > n.

n is prime by Pocklington's theorem.