Mega Millions jackpot grows to $640 million -- could go higher

People across the country are buying tickets for tonight's Mega Millions jackpot, which has ballooned to more than $540 million. NBC's Stephanie Gosk reports.

By msnbc.com news services

The Mega Millions lottery hit $640 million Friday, according to lottery officials, raising what was already a record-shattering prize.

That's a cash payout of $462 million, according to the Mega Millions web site.

The even larger prize is expected to add to the lottery frenzy across the country. Hopeful future-millionaires have formed long lines at stores across the 42 states, plus Washington, D.C. and the Virgin Islands, where tickets are sold.

What to buy when you win the jackpot

The drawing for the fortune is set for late Friday in Atlanta.

Nobody matched all six numbers in Tuesday's regular draw, and the total jackpot has been growing since.

Players pay $1 for a ticket and must pick five numbers from 1 to 56 plus a Mega number from 1 to 46 to win the jackpot. The odds of winning are 1 in about 176 million, according to the official Mega Millions website.

Why even skeptics are rushing to buy a Mega Millions ticket

The largest Mega Millions jackpot ever won was $390 million in March 2007, when the prize was split between two tickets sold in Georgia and New Jersey.

U.S. News - Mega Millions jackpot grows to $640 million -- could go higher