Command line to find prime factors up to about 35-digit
echo 870531918755444788521494434185778500590102497298646184824845309276175467746437979258134439900447462111559486175747933354115832007088318584636477125461818737421046952176346585718473683453229 | ecm -n -c 825 1e6
Command line to find prime factors up to about 40-digit
echo 870531918755444788521494434185778500590102497298646184824845309276175467746437979258134439900447462111559486175747933354115832007088318584636477125461818737421046952176346585718473683453229 | ecm -n -c 2336 3e6
Command line to find prime factors up to about 45-digit
echo 870531918755444788521494434185778500590102497298646184824845309276175467746437979258134439900447462111559486175747933354115832007088318584636477125461818737421046952176346585718473683453229 | ecm -n -c 4479 11e6
Command line to find prime factors up to about 50-digit
echo 870531918755444788521494434185778500590102497298646184824845309276175467746437979258134439900447462111559486175747933354115832007088318584636477125461818737421046952176346585718473683453229 | ecm -n -c 7553 43e6