And sometimes these IQ numbers were extrapolated and, shall we say, stretched a bit. For example, wrt Marilyn Vos Savant: "Miss Savant was given an old version of the Stanford-Binet (Terman & Merrill 1937), which did, indeed, use the antiquated formula of MA/CA × 100. But in the test manual’s norms, the Binet does not permit IQs to rise above 170 at any age. So, the psychologist who came up with an IQ of 228 committed an extrapolation of a misconception, thereby violating almost every rule imaginable concerning the meaning of IQs." https://www.scienceabc.com/humans/who-are-some-of-the-people-with-the-highest-iq.html

It's also interesting that with the exceptions of Einstein, Hawking and Kasparov, these people have managed to remain obscure, known only for their high IQ scores.