Primality proof for n = 27869213:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=995329.html>995329 is prime.</a>
<br>b^((n-1)/995329)-1 mod n = 17612538, which is a unit, inverse 7801839.
<p>(995329) divides n-1.
<p>(995329)^2 > n.
<p>n is prime by Pocklington's theorem.