Primality proof for n = 983685833987:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=8336320627.html>8336320627 is prime.</a>
<br>b^((n-1)/8336320627)-1 mod n = 950236973967, which is a unit, inverse 137188557913.
<p>(8336320627) divides n-1.
<p>(8336320627)^2 > n.
<p>n is prime by Pocklington's theorem.