Primality proof for n = 641579:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=45827.html>45827 is prime.</a>
<br>b^((n-1)/45827)-1 mod n = 16383, which is a unit, inverse 345559.
<p>(45827) divides n-1.
<p>(45827)^2 > n.
<p>n is prime by Pocklington's theorem.