Command line to find prime factors up to about 35-digit
echo 7783768068039254330762314966624629869731617131768898766117637842657729900318814539178177072474954104643429683389739885393853398266391 | ecm -n -c 786 1e6
Command line to find prime factors up to about 40-digit
echo 7783768068039254330762314966624629869731617131768898766117637842657729900318814539178177072474954104643429683389739885393853398266391 | ecm -n -c 2318 3e6
Command line to find prime factors up to about 45-digit
echo 7783768068039254330762314966624629869731617131768898766117637842657729900318814539178177072474954104643429683389739885393853398266391 | ecm -n -c 4475 11e6
Command line to find prime factors up to about 50-digit
echo 7783768068039254330762314966624629869731617131768898766117637842657729900318814539178177072474954104643429683389739885393853398266391 | ecm -n -c 7553 43e6