Primality proof for n = 22157:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=191.html>191 is prime.</a>
<br>b^((n-1)/191)-1 mod n = 1217, which is a unit, inverse 2913.
<p>(191) divides n-1.
<p>(191)^2 > n.
<p>n is prime by Pocklington's theorem.