Command line to find prime factors up to about 35-digit
echo 3558191267332394437084509852343283054495674668830243271205718754451956767779787910451319385297183140705741226270253730815689704519576511927922136664899717961809638656719976101715093588466935256121 | ecm -n -c 825 1e6
Command line to find prime factors up to about 40-digit
echo 3558191267332394437084509852343283054495674668830243271205718754451956767779787910451319385297183140705741226270253730815689704519576511927922136664899717961809638656719976101715093588466935256121 | ecm -n -c 2336 3e6
Command line to find prime factors up to about 45-digit
echo 3558191267332394437084509852343283054495674668830243271205718754451956767779787910451319385297183140705741226270253730815689704519576511927922136664899717961809638656719976101715093588466935256121 | ecm -n -c 4479 11e6
Command line to find prime factors up to about 50-digit
echo 3558191267332394437084509852343283054495674668830243271205718754451956767779787910451319385297183140705741226270253730815689704519576511927922136664899717961809638656719976101715093588466935256121 | ecm -n -c 7553 43e6