Primality proof for n = 858239144413883:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=326257.html>326257 is prime.</a>
<br>b^((n-1)/326257)-1 mod n = 736392267752739, which is a unit, inverse 405260866868181.
<p><a href=71471.html>71471 is prime.</a>
<br>b^((n-1)/71471)-1 mod n = 725394242153382, which is a unit, inverse 189798240383950.
<p>(71471 * 326257) divides n-1.
<p>(71471 * 326257)^2 > n.
<p>n is prime by Pocklington's theorem.