Primality proof for n = 2400573761:
<p>Take b = 3.
<p>b^(n-1) mod n = 1.
<p><a href=1663.html>1663 is prime.</a>
<br>b^((n-1)/1663)-1 mod n = 1701215345, which is a unit, inverse 1534051064.
<p><a href=347.html>347 is prime.</a>
<br>b^((n-1)/347)-1 mod n = 1380226035, which is a unit, inverse 1288538855.
<p>(347 * 1663) divides n-1.
<p>(347 * 1663)^2 > n.
<p>n is prime by Pocklington's theorem.