Primality proof for n = 28723789958641:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=17097494023.html>17097494023 is prime.</a>
<br>b^((n-1)/17097494023)-1 mod n = 4906311729342, which is a unit, inverse 24207144520723.
<p>(17097494023) divides n-1.
<p>(17097494023)^2 > n.
<p>n is prime by Pocklington's theorem.