Primality proof for n = 2698097:
Take b = 2.
b^(n-1) mod n = 1.
168631 is prime. b^((n-1)/168631)-1 mod n = 65535, which is a unit, inverse 347354.
(168631) divides n-1.
(168631)^2 > n.
n is prime by Pocklington's theorem.