Primality proof for n = 212102557441:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=135049.html>135049 is prime.</a>
<br>b^((n-1)/135049)-1 mod n = 199221958325, which is a unit, inverse 2061844630.
<p><a href=409.html>409 is prime.</a>
<br>b^((n-1)/409)-1 mod n = 23719261883, which is a unit, inverse 107862837290.
<p>(409 * 135049) divides n-1.
<p>(409 * 135049)^2 > n.
<p>n is prime by Pocklington's theorem.