Primality proof for n = 1948699:

Take b = 2.

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

523 is prime.
b^((n-1)/523)-1 mod n = 114069, which is a unit, inverse 994397.

23 is prime.
b^((n-1)/23)-1 mod n = 1034814, which is a unit, inverse 593413.

(23 * 523) divides n-1.

(23 * 523)^2 > n.

n is prime by Pocklington's theorem.