Primality proof for n = 20850849555552798305550425353:
<p>Take b = 2.
<p>b^(n-1) mod n = 1.
<p><a href=194995755782084489.html>194995755782084489 is prime.</a>
<br>b^((n-1)/194995755782084489)-1 mod n = 13958705882451561869515934397, which is a unit, inverse 5226651491880192909373901355.
<p>(194995755782084489) divides n-1.
<p>(194995755782084489)^2 > n.
<p>n is prime by Pocklington's theorem.