Primality proof for n = 5621767:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=32309.html>32309 is prime.</a>
<br>b^((n-1)/32309)-1 mod n = 2927843, which is a unit, inverse 3011739.
<p>(32309) divides n-1.
<p>(32309)^2 > n.
<p>n is prime by Pocklington's theorem.