Command line to find prime factors up to about 20-digit
echo 477774003799284931757027533443930044058200204000675666012749694678436957568955126173252976787042882398355584631203659863078083498304434616973 | ecm -n -c 74 11e3
Command line to find prime factors up to about 25-digit
echo 477774003799284931757027533443930044058200204000675666012749694678436957568955126173252976787042882398355584631203659863078083498304434616973 | ecm -n -c 214 5e4
Command line to find prime factors up to about 30-digit
echo 477774003799284931757027533443930044058200204000675666012749694678436957568955126173252976787042882398355584631203659863078083498304434616973 | ecm -n -c 430 25e4
Command line to find prime factors up to about 35-digit
echo 477774003799284931757027533443930044058200204000675666012749694678436957568955126173252976787042882398355584631203659863078083498304434616973 | ecm -n -c 904 1e6
Command line to find prime factors up to about 40-digit
echo 477774003799284931757027533443930044058200204000675666012749694678436957568955126173252976787042882398355584631203659863078083498304434616973 | ecm -n -c 2350 3e6