Command line to find prime factors up to about 20-digit
echo 64265835491045736960072278010454722698450882502010690144263974659116792275108799238312632212437706878940811504701629222452158624703328639692104075334253854786574645906321896465667859 | ecm -n -c 74 11e3
Command line to find prime factors up to about 25-digit
echo 64265835491045736960072278010454722698450882502010690144263974659116792275108799238312632212437706878940811504701629222452158624703328639692104075334253854786574645906321896465667859 | ecm -n -c 214 5e4
Command line to find prime factors up to about 30-digit
echo 64265835491045736960072278010454722698450882502010690144263974659116792275108799238312632212437706878940811504701629222452158624703328639692104075334253854786574645906321896465667859 | ecm -n -c 430 25e4
Command line to find prime factors up to about 35-digit
echo 64265835491045736960072278010454722698450882502010690144263974659116792275108799238312632212437706878940811504701629222452158624703328639692104075334253854786574645906321896465667859 | ecm -n -c 904 1e6
Command line to find prime factors up to about 40-digit
echo 64265835491045736960072278010454722698450882502010690144263974659116792275108799238312632212437706878940811504701629222452158624703328639692104075334253854786574645906321896465667859 | ecm -n -c 2350 3e6