He says he’s a Harvard grad but so far nobody has seen a shred of proof. And then the claim that he is a “Professor of Constitutional law” when he has shown time and time again he knows absolutely nothing about the Constitution.
He's probably of above-average intelligence (but not super-smart like a few of the Presidents), just lazy and ignorant, because he has had things handed to him all his life without having to put much effort into it. He sees the Presidency as alternating between playing golf and making campaign speeches. Any real work is left to others.