[maxxdude1234]

Just for the record artur, I agree with everything you say here. BUT, the torque a motor needs to produce depends solely upon the load put upon it. The factors you hightlighted (number of turns, can diameter, can length, magnet size) affect the 'kt' of a particular motor. The 'kt' of a motor will affect how much current the motor will need to draw to produce enough torque to overcome that load.
Not critizising you; just trying to clear this up for everyone else

ps. to all those people who say 'if this formula is correct; power = torque x rpm' - there is no 'if' about it. This formula stems from moment calculations in physics, and believe me its correct!