Command line to find prime factors up to about 20-digit
echo 175790772573168628123882459544293863504571995468093214648655228684550209634532372946253410661518081657531896227593819478128938329639194607798477286564667 | ecm -n -c 74 11e3
Command line to find prime factors up to about 25-digit
echo 175790772573168628123882459544293863504571995468093214648655228684550209634532372946253410661518081657531896227593819478128938329639194607798477286564667 | ecm -n -c 214 5e4
Command line to find prime factors up to about 30-digit
echo 175790772573168628123882459544293863504571995468093214648655228684550209634532372946253410661518081657531896227593819478128938329639194607798477286564667 | ecm -n -c 430 25e4
Command line to find prime factors up to about 35-digit
echo 175790772573168628123882459544293863504571995468093214648655228684550209634532372946253410661518081657531896227593819478128938329639194607798477286564667 | ecm -n -c 904 1e6
Command line to find prime factors up to about 40-digit
echo 175790772573168628123882459544293863504571995468093214648655228684550209634532372946253410661518081657531896227593819478128938329639194607798477286564667 | ecm -n -c 2350 3e6