A man shows his Mega Millions lottery ticket he purchased at a gas station in Dallas, Texas.

A woman fills out her Mega Millions ticket at The Gallery Shop on Dec. 17 in Washington. The Mega Millions jackpot has soared to $636 million, making it the second largest lottery jackpot in U.S. history.

The ultimate Christmas gift that could keep on giving and giving and giving. 

And the winning Mega Millions jackpot numbers are ... 8-20-14-17-39 and 7. 
If, by chance, you happen to hold a Mega Millions ticket with these six numbers, you've just won $636 million, the second-biggest lottery jackpot of all time. 

Take a deep breath. While the drawing was held at 11 p.m. ET Tuesday, lottery officials aren't expected to officially proclaim a winner — if there is one or more — until early Wednesday morning. 

Odds of winning: about 1 in 259 million. 

A woman fills out a form to buy a Mega Millions ticket at The Gallery Shop.

Tuesday's jackpot had rolled over 21 straight drawings since Oct. 4, worth a lump, sum, pre-tax payout worth $314.2 million. If there's no winner, Friday night's jackpot could surge past $825 million, eviscerating the $656 million record jackpot split by three winners in March 2012. 

And if it rolls over Friday? It could hit a whopping $1 billion by next Tuesday's Christmas Eve drawing, says Virginia lottery director Paula Otto, lead director for Mega Millions, played in 43 states, Washington, D.C. and the U.S. Virgin Islands. 

Ticket sales — the topic of TV, radio, social media and burgeoning office pools — surged in the hours leading up to the drawing, even though up to 75% of the possible number combinations were expected to be picked. 

A woman fills out her Mega Millions ticket at The Gallery Shop on Dec. 17 in Washington. The Mega Millions jackpot has soared to $636 million, making it the second largest lottery jackpot in U.S. history. 

"They're buying like crazy," Ahmed Karim, the owner of a New Brunswick 7-Eleven, told nj.com. 

"Even though the odds are against you, it's just the excitement of, 'Hey, I might wake up one day and be a millionaire,' " says Chris Scales, 31, of Nashville. The hot dog vendor says he earns about $35,000 a year "if I really hustle." 

The incredibly remote odds don't really sink in for people, says George Loewenstein, a professor of economics and psychology at Carnegie Mellon University who has researched the motives of lottery ticket buyers."People don't really understand probabilities at all," he says. "Once you have a bunch of zeroes, it doesn't matter how many you have — one in 10,000, one in a million or one in a billion. … People do understand the meaning of the word 'largest.' They overreact to one dimension and underreact to the other."  

A cashier hands a customer her Mega Millions ticket at The Gallery Shop.

Tuesday's drawing aside, Mega Millions jackpots are likely to continue swelling after lottery officials boosted their potential payouts.  

Originally, customers chose five numbers from 1-56 and one number from 1-46. The new structure has customers choosing five numbers from 1-75 and one number from 1-15. That sliced the odds of winning from 1 in 176 million to 1 in 259 million.  

Longtime lottery watcher Gail Howard says that with the odds of hitting the jackpot so small, ticket buyers should buy no more than one.  

"Your odds are not going to improve that much if you buy 1 ticket or 1,000,'' says Howard, author of Lottery Master Guide. "I also think you should pick your own numbers rather than let a (point of sale) computer do it."  

The current jackpot started at $12 million Oct. 4. By last week, it was up to $425 million, then $586 million on Monday before being raised to $636 million Tuesday morning. 

A cashier sells a Mega Millions lottery ticket at a gas station in Dallas. A woman plays the Mega Millions lottery at a shop in Penn Station in New York City. A woman picks her Mega Millions lottery numbers at a shop in Penn Station. A man buys a Mega Millions lottery ticket at a corner newsstand in New York. A man buys a lottery ticket in New York City. Mega Millions tickets rest on a convenience store counter in Lawrence, Kan. Mega Millions forms are ready for customers at a convenience store in Lawrence. A sales clerk holds Mega Millions lottery tickets on Dec. 16 in Decatur, Ga. The jackpot for the drawing on Dec. 17 is worth an estimated $586 million. A store worker holds Mega Millions lottery tickets in Decatur, Ga. John Hollis shows off the Mega Millions lottery tickets he purchased at the Fuel City convenience store in Dallas. Mega Millions lottery tickets are sold at the Fuel City convenience store in Dallas. Anita Watson, assistant manager at Energy Express convenience store, touches a screen to print out a Mega Millions lottery ticket in St. Louis. Scott Hoormann holds Mega Millions lottery tickets he purchased at Energy Express in St. Louis. Energy Express assistant manager Anita Watson, right, sells a Mega Millions lottery ticket to Brian Thomason in St. Louis. Chad Cuneo displays Mega Millions lottery tickets he purchased at a newsstand on Dec. 13 in Philadelphia.  Heavy sales prompted lottery officials to boost the estimated jackpot payout for that day's drawing to $425 million. A custumer buys a Mega Millions lottery ticket at a newsstand in Philadelphia on Dec. 13. Chad Cuneo counts out money to purchase his Mega Millions lottery tickets. A woman buys Mega Millions lottery tickets at a newsstand in Philadelphia. A man purchases Mega Millions lottery tickets at the Bi Rite market in Olmsted Township, Ohio. Jim Hess checks his Mega Millions lottery tickets after buying them at the Bi Rite market. Janet Humpal, right, buys Mega Millions lottery tickets from cashier Brittany Beardon at the Bi Rite market in Olmsted Township. Mega Millions lottery tickets print at the Bi Rite market.A Mega Millions lottery ticket is displayed in Springfield, Ill. Women laugh as they look at the Mega Millions tickets they bought for a pool of co-workers at The Gallery Shop.