Command line to find prime factors up to about 20-digit
echo 26601573310789569322428570212869305953758780716278117469612063456631090930965799788522376776149446687396891419353149500981513594946203757148221797823266052095667247 | ecm -n -c 74 11e3
Command line to find prime factors up to about 25-digit
echo 26601573310789569322428570212869305953758780716278117469612063456631090930965799788522376776149446687396891419353149500981513594946203757148221797823266052095667247 | ecm -n -c 214 5e4
Command line to find prime factors up to about 30-digit
echo 26601573310789569322428570212869305953758780716278117469612063456631090930965799788522376776149446687396891419353149500981513594946203757148221797823266052095667247 | ecm -n -c 430 25e4
Command line to find prime factors up to about 35-digit
echo 26601573310789569322428570212869305953758780716278117469612063456631090930965799788522376776149446687396891419353149500981513594946203757148221797823266052095667247 | ecm -n -c 904 1e6
Command line to find prime factors up to about 40-digit
echo 26601573310789569322428570212869305953758780716278117469612063456631090930965799788522376776149446687396891419353149500981513594946203757148221797823266052095667247 | ecm -n -c 2350 3e6