Did Einstein know his own phone number?
It’s quite likely he did not have one at the time he came up with Special Relativity. He was still a patent examiner, a low-level bureaucrat. And it was only 1905. And probably likely he didn’t have one by the time the final version of General Relativity was published 11 years later.
I think memorizing trivia is not much more than a quirky and mostly useless talent (that I don’t have, public school or not). But I will put my theoretical skills at comprehending special or general relativity up against the author’s or any of the fill-in-the-blank trivia “geniuses” any day.