Command line to find prime factors up to about 20-digit
echo 3555207095596874059093022653030557476400549185657127779363050711219171348248885576997941683682191594431627017939174302149042794928815879758855123596648038931988283101 | ecm -n -c 74 11e3
Command line to find prime factors up to about 25-digit
echo 3555207095596874059093022653030557476400549185657127779363050711219171348248885576997941683682191594431627017939174302149042794928815879758855123596648038931988283101 | ecm -n -c 214 5e4
Command line to find prime factors up to about 30-digit
echo 3555207095596874059093022653030557476400549185657127779363050711219171348248885576997941683682191594431627017939174302149042794928815879758855123596648038931988283101 | ecm -n -c 430 25e4
Command line to find prime factors up to about 35-digit
echo 3555207095596874059093022653030557476400549185657127779363050711219171348248885576997941683682191594431627017939174302149042794928815879758855123596648038931988283101 | ecm -n -c 904 1e6
Command line to find prime factors up to about 40-digit
echo 3555207095596874059093022653030557476400549185657127779363050711219171348248885576997941683682191594431627017939174302149042794928815879758855123596648038931988283101 | ecm -n -c 2350 3e6