Primality proof for n = 991057:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=1877.html>1877 is prime.</a>
<br>b^((n-1)/1877)-1 mod n = 89255, which is a unit, inverse 708158.
<p>(1877) divides n-1.
<p>(1877)^2 > n.
<p>n is prime by Pocklington's theorem.