Command line to find prime factors up to about 40-digit
echo 481509536157157846687573679628626184451407277308556047171707679710808125914428945299129159679709131959771707888809585049660629129007638882227907567802704625912279 | ecm -n -c 2104 3e6
Command line to find prime factors up to about 45-digit
echo 481509536157157846687573679628626184451407277308556047171707679710808125914428945299129159679709131959771707888809585049660629129007638882227907567802704625912279 | ecm -n -c 4439 11e6
Command line to find prime factors up to about 50-digit
echo 481509536157157846687573679628626184451407277308556047171707679710808125914428945299129159679709131959771707888809585049660629129007638882227907567802704625912279 | ecm -n -c 7548 43e6
Command line to find prime factors up to about 55-digit
echo 481509536157157846687573679628626184451407277308556047171707679710808125914428945299129159679709131959771707888809585049660629129007638882227907567802704625912279 | ecm -n -c 17769 11e7