Primality proof for n = 196911713:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=6153491.html>6153491 is prime.</a>
<br>b^((n-1)/6153491)-1 mod n = 159821322, which is a unit, inverse 114640451.
<p>(6153491) divides n-1.
<p>(6153491)^2 > n.
<p>n is prime by Pocklington's theorem.