Primality proof for n = 166021:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=2767.html>2767 is prime.</a>
<br>b^((n-1)/2767)-1 mod n = 141431, which is a unit, inverse 162787.
<p>(2767) divides n-1.
<p>(2767)^2 > n.
<p>n is prime by Pocklington's theorem.