Primality proof for n = 1224481:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=2551.html>2551 is prime.</a>
<br>b^((n-1)/2551)-1 mod n = 921658, which is a unit, inverse 1100631.
<p>(2551) divides n-1.
<p>(2551)^2 > n.
<p>n is prime by Pocklington's theorem.