20740...12957 (1045-digits)

This number is a prime.

Suppose you were to take this variant of efdtt.c,

unsigned char i[5],l[2048],m;main(n){for(read(0,i,5);read(0,l,n=2048);write(1,l ,n))if(l[m=l[13]%8+20]/16%4==1){int p=a(1)17^256+a(0)8,q=a(2)0,r=a(4)17^a(3)9^q *2-q%8^8,u=0,w=26;for(l[m]-=16;--w;r*=2)u=u*2^p&1,p=p/2^r&1<<24;for(r=127;++r<n ;w=w>m)w+=m=p^p/8^p>>4^p>>12,p=p>>8^m<<17,u^=u>>14,m=u^u*8^u<<6,u=u>>8^m<<9,q=l [r],q="7Wo~'G_\216"[q&7]+2^"cr3sfw6v;*k+>/n."[q>>4]*2^q*257/8,l[r]=q^(q&q*2&34) *6^w+~m;}}

a program that will allow you to play a DVD on a computer, and then convert each character in the code to its 8-bit ascii equivalent, then view this string of bits as a single number. What do you get? This illegal prime!

This number was found to be a probable prime by Charles M. Hannum (the original author of efdtt.c) and proven prime by Phil Carmody. [Carmody and Caldwell]