What is the maximum possible value of the angular momentum for an outer electron in the ground state of a germanium atom?

What is the maximum possible value of the angular momentum for an outer electron in the ground state of a germanium atom?
The answer is 3.65e-34 kg · m2/s
Can someone please explain this to me very thouroghly because I am so confused as to how to do this question and every one I have seen posted on chegg has been answered incorrectly.