If you can exert a force of 500 Newtons, then you should be able to lift an object that has a normal force of 500 Newtons or less. Since Force = mass x acceleration, the normal force is calculated as the mass of the object multiplied by the acceleration of gravity. If the mass is in kilograms and the acceleration is in Meters/sec2, the force unit is Newtons.
In your question, F = 500 N
On Earth, a = 9.91 m/s2, so F=ma gets you:
500 = m(9.81)
500/9.81 = m
54.9 kg =m
So you can move a mass of 54.9 kg on Earth.
500 = m(3.74)
500/3.74 = m
133.7 = m
On Mars, you can move a mass of 133.7 kg.