Primality proof for n = 85831:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=2861.html>2861 is prime.</a>
<br>b^((n-1)/2861)-1 mod n = 81844, which is a unit, inverse 38061.
<p>(2861) divides n-1.
<p>(2861)^2 > n.
<p>n is prime by Pocklington's theorem.