Command line to find prime factors up to about 20-digit
echo 6757872193567318388538500227189105570035047793192001207475336814931644819508615641168755976521894296865922024131000944435476099198418217948038994826090300707 | ecm -n -c 74 11e3
Command line to find prime factors up to about 25-digit
echo 6757872193567318388538500227189105570035047793192001207475336814931644819508615641168755976521894296865922024131000944435476099198418217948038994826090300707 | ecm -n -c 214 5e4
Command line to find prime factors up to about 30-digit
echo 6757872193567318388538500227189105570035047793192001207475336814931644819508615641168755976521894296865922024131000944435476099198418217948038994826090300707 | ecm -n -c 430 25e4
Command line to find prime factors up to about 35-digit
echo 6757872193567318388538500227189105570035047793192001207475336814931644819508615641168755976521894296865922024131000944435476099198418217948038994826090300707 | ecm -n -c 904 1e6
Command line to find prime factors up to about 40-digit
echo 6757872193567318388538500227189105570035047793192001207475336814931644819508615641168755976521894296865922024131000944435476099198418217948038994826090300707 | ecm -n -c 2350 3e6