Primality proof for n = 21691107791071112804746088983950791:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=24453091069698428153.html>24453091069698428153 is prime.</a>
<br>b^((n-1)/24453091069698428153)-1 mod n = 12897629273018855099775043891234934, which is a unit, inverse 3542555888969238127864350465858182.
<p>(24453091069698428153) divides n-1.
<p>(24453091069698428153)^2 > n.
<p>n is prime by Pocklington's theorem.