"Forbes" just released its annual list of the WORLD'S RICHEST PEOPLE. Here are the six things to know . . .
1. After four years off, BILL GATES is back to being the wealthiest person in the world. Even though he's TRYING to donate his money, Gates's net worth went up $9 billion last year to $76 billion.
2. There are now 1,645 billionaires in the world with a combined net worth of $6.4 trillion.
3. There are a record 172 female billionaires on the list. That's up from 138 last year.
4. MARK ZUCKERBERG had the biggest gain of anyone on the list. His net worth went up $15.2 billion from last year, to $28.5 billion total. He ranks 21st on the list.
5. There are 31 billionaires in the world under age 40.
6. Some of the new billionaires this year are the two guys who founded WhatsApp and just got a $19 billion deal with Facebook . . . Michael Kors . . . Ev Williams, the founder of Twitter . . . and Vince McMahon of the WWE. (Forbes)