Primality proof for n = 2663886769:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=227.html>227 is prime.</a>
<br>b^((n-1)/227)-1 mod n = 676872375, which is a unit, inverse 2648350256.
<p><a href=89.html>89 is prime.</a>
<br>b^((n-1)/89)-1 mod n = 1442155822, which is a unit, inverse 2563536608.
<p><a href=67.html>67 is prime.</a>
<br>b^((n-1)/67)-1 mod n = 189440380, which is a unit, inverse 2419164473.
<p>(67 * 89 * 227) divides n-1.
<p>(67 * 89 * 227)^2 > n.
<p>n is prime by Pocklington's theorem.