Primality proof for n = 1490039853025247:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=833843.html>833843 is prime.</a>
<br>b^((n-1)/833843)-1 mod n = 651687852898634, which is a unit, inverse 1381331602035500.
<p><a href=3331.html>3331 is prime.</a>
<br>b^((n-1)/3331)-1 mod n = 151787127010308, which is a unit, inverse 584155503533472.
<p>(3331 * 833843) divides n-1.
<p>(3331 * 833843)^2 > n.
<p>n is prime by Pocklington's theorem.