Primality proof for n = 990435552551:

Take b = 2.

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

2245631 is prime.
b^((n-1)/2245631)-1 mod n = 957469282789, which is a unit, inverse 59801225846.

(2245631) divides n-1.

(2245631)^2 > n.

n is prime by Pocklington's theorem.