How much voltage difference will lead to saturation, LM741?
The main one would be the large signal voltage gain. This gives the output in V for a difference in input measured in mV.

You also need to look at the input offset voltage which in this case is 2 to 6 mV. If you take the worst case, 6 mV, and maximum large signal voltage gain of 200 you can see that the output would be saturated without any difference between the inputs.

The 741 is ancient and should only be used to learn about why we don't use them anymore.