Bill Gates became a billionaire in 1987 at age 31 — the youngest self-made billionaire in the world at the time. Microsoft’s March 1986 IPO had already made him worth roughly $350 million overnight. Mark Zuckerberg took the youngest-self-made-billionaire title from him in 2008, at age 23.

Bill Gates topped the Forbes list of the world’s richest people for most years between 1995 and 2017 — interrupted only by Warren Buffett in 2008 and by Carlos Slim from 2010 through 2013. Jeff Bezos didn’t overtake him until 2018.

Bill Gates has a published mathematics paper. As a Harvard undergraduate he co-wrote “Bounds for Sorting by Prefix Reversal” (1979) on the “pancake sorting” problem with professor Christos Papadimitriou — and the bound he proved stood as the best known for roughly 30 years.

One of Bill Gates’s own coding credits is DONKEY.BAS, a crude driving game he co-wrote in 1981 (with Neil Konzen) to ship with the first IBM PC. Apple’s Macintosh team later singled it out as an embarrassment.