(NEW YORK) -- The Mega Millions jackpot has soared to an estimated $685 million ahead of Friday night's drawing.
The prize is the largest Mega Millions prize ever offered in the final week of any year, according to the lottery.
The cash prize option is estimated to be $347.8 million.
The jackpot has grown over the 21 drawings since the lottery's jackpot was last won on Oct. 14, when two ticket winners split a $502 million prize.
It's continued to climb since the most recent drawing; after no tickets matched all six winning numbers in Tuesday's drawing, the jackpot was estimated to reach $640 million.
Only six Mega Millions jackpots have been won this year. Winning tickets were in California, Florida, New York, Minnesota, Illinois and Tennessee.
The Mega Millions jackpot has soared past $600 million just five other times in its more than 20-year history, according to the lottery.
In July, the jackpot surpassed the $1 billion mark for only the third time in its history.
The historic $1.34 billion prize was won by an anonymous ticket owner in Des Plaines, Illinois.
Mega Millions is played in 45 states plus Washington, D.C., and the U. S. Virgin Islands.
The next drawing is at 11 p.m. ET Friday.