Command line to find prime factors up to about 20-digit
echo 42382461365925566589361872338864222772993946721282262886407213633419478007736146697727909341560887486488960796728980373896239574744433823648184301 | ecm -n -c 74 11e3
Command line to find prime factors up to about 25-digit
echo 42382461365925566589361872338864222772993946721282262886407213633419478007736146697727909341560887486488960796728980373896239574744433823648184301 | ecm -n -c 214 5e4
Command line to find prime factors up to about 30-digit
echo 42382461365925566589361872338864222772993946721282262886407213633419478007736146697727909341560887486488960796728980373896239574744433823648184301 | ecm -n -c 430 25e4
Command line to find prime factors up to about 35-digit
echo 42382461365925566589361872338864222772993946721282262886407213633419478007736146697727909341560887486488960796728980373896239574744433823648184301 | ecm -n -c 904 1e6
Command line to find prime factors up to about 40-digit
echo 42382461365925566589361872338864222772993946721282262886407213633419478007736146697727909341560887486488960796728980373896239574744433823648184301 | ecm -n -c 2350 3e6