Primality proof for n = 921589:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=1259.html>1259 is prime.</a>
<br>b^((n-1)/1259)-1 mod n = 687365, which is a unit, inverse 781126.
<p>(1259) divides n-1.
<p>(1259)^2 > n.
<p>n is prime by Pocklington's theorem.