Command line to find prime factors up to about 20-digit
echo 65261778610059282538505506212862343345224856589130017113255212122608100321035202928930089674335343491886183269497516428181519860883855118033755582408721707568733452750608438702704678300209459 | ecm -n -c 74 11e3
Command line to find prime factors up to about 25-digit
echo 65261778610059282538505506212862343345224856589130017113255212122608100321035202928930089674335343491886183269497516428181519860883855118033755582408721707568733452750608438702704678300209459 | ecm -n -c 214 5e4
Command line to find prime factors up to about 30-digit
echo 65261778610059282538505506212862343345224856589130017113255212122608100321035202928930089674335343491886183269497516428181519860883855118033755582408721707568733452750608438702704678300209459 | ecm -n -c 430 25e4
Command line to find prime factors up to about 35-digit
echo 65261778610059282538505506212862343345224856589130017113255212122608100321035202928930089674335343491886183269497516428181519860883855118033755582408721707568733452750608438702704678300209459 | ecm -n -c 904 1e6
Command line to find prime factors up to about 40-digit
echo 65261778610059282538505506212862343345224856589130017113255212122608100321035202928930089674335343491886183269497516428181519860883855118033755582408721707568733452750608438702704678300209459 | ecm -n -c 2350 3e6