Primality proof for n = 123127:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=20521.html>20521 is prime.</a>
<br>b^((n-1)/20521)-1 mod n = 63, which is a unit, inverse 9772.
<p>(20521) divides n-1.
<p>(20521)^2 > n.
<p>n is prime by Pocklington's theorem.