Command line to find prime factors up to about 35-digit
echo 6686260524329757025828204085238554917983237179883508757160174103890578066510149968722446860438005210576514098574762231902213794075480296495200883980197588361161967323976800742699964649877251236405535784308307 | ecm -n -c 825 1e6
Command line to find prime factors up to about 40-digit
echo 6686260524329757025828204085238554917983237179883508757160174103890578066510149968722446860438005210576514098574762231902213794075480296495200883980197588361161967323976800742699964649877251236405535784308307 | ecm -n -c 2336 3e6
Command line to find prime factors up to about 45-digit
echo 6686260524329757025828204085238554917983237179883508757160174103890578066510149968722446860438005210576514098574762231902213794075480296495200883980197588361161967323976800742699964649877251236405535784308307 | ecm -n -c 4479 11e6
Command line to find prime factors up to about 50-digit
echo 6686260524329757025828204085238554917983237179883508757160174103890578066510149968722446860438005210576514098574762231902213794075480296495200883980197588361161967323976800742699964649877251236405535784308307 | ecm -n -c 7553 43e6