Primality proof for n = 918583:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=21871.html>21871 is prime.</a>
<br>b^((n-1)/21871)-1 mod n = 627306, which is a unit, inverse 27156.
<p>(21871) divides n-1.
<p>(21871)^2 > n.
<p>n is prime by Pocklington's theorem.