There are a lot of very smart people in this ole world, but Dr Knuth stands above them.
There may be some that are called "smarter" but in terms of applied math and science, he is way, way up there.
Yes, the same Dr Knuth that wrote the massive Art of Computer Programming way back in 1973.
On par with Georg Cantor, perhaps? See https://en.wikipedia.org/wiki/Cantor%27s_paradox