Primality proof for n = 550457:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=829.html>829 is prime.</a>
<br>b^((n-1)/829)-1 mod n = 447875, which is a unit, inverse 411461.
<p>(829) divides n-1.
<p>(829)^2 > n.
<p>n is prime by Pocklington's theorem.