How to calculate how much wight a motor can lift?
Torque and Radius of the shaft are the necessary specs that you need for a first approach of the calculation.

The force at the radius of the hollow shaft can by calculated as

F = M / r = 450 Nm / 0,02 m = 22,5 kN

Depending on which planet you want to use the device, you can calculate the mass that you can lift against gravitational force. For earth it can be calculated as follows:

m = F / g = 22,5 kN / 9,81 m/s^2 = 2293,58 kg.