Primality proof for n = 391669282183:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=1569301.html>1569301 is prime.</a>
<br>b^((n-1)/1569301)-1 mod n = 126544476127, which is a unit, inverse 71262010238.
<p>(1569301) divides n-1.
<p>(1569301)^2 > n.
<p>n is prime by Pocklington's theorem.