A Georgia woman who used family members' birth dates to select the winning numbers in Tuesday's $648 million Mega Millions jackpot came forward to claim her portion of the prize Wednesday, just hours after discovering she held a winning ticket.

Ira Curry, of Stone Mountain, was identified as one of two winners of the jackpot, the second-largest on record. Georgia lottery officials said the ticket was "a last minute purchase" in an Atlanta area Gateway Newstand. The store is in the affluent Buckhead district north of Atlanta.

"She was driving to work, she had the radio on, and she knew she had the Mega ball number (7). Her daughter quickly looked up the winning numbers,'' said Georgia Lottery director Debbie Alford. "Between joyful tears and laughter on the daughter's part, she relayed to her mother that she'd won."

Curry, who did not attend a press briefing announcing her win, will split a lump sum payout valued at about $346.7 million with a ticket holder in San Jose, Calif. Alford said after federal and Georgia state taxes are factored in, Curry will receive about $120 million.

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Alford said she was baffled Curry stepped forward so quickly. Typically, jackpot winners wait days, or weeks, to surface - and in Georgia, winners have 180 days to claim prizes. The California ticket holder, who has yet to come forward, has a year to collect their half.

Alford revealed no details about Curry or her family. A person who answered a call at a phone listing for Curry said, "We are not interested in any publicity, thank you for calling," then hung up.

Young Soo Lee, who owns the store where Curry bought her ticket, relished Curry's good fortune.

"I'm so excited and nervous too," Soo Lee told Atlanta's Fox 5 News early Wednesday. Soo Lee, who said she sold about 1,300 tickets Tuesday, will also benefit. Her story will receive about $1 million for selling a winning ticket.

In San Jose, gift shop owner Thuy Nguyen was equally thrilled.

"The lottery called me and let me know... Whoa!" Nguyen told the San Jose Mercury News. "I am so happy, I feel good."

Tuesday's jackpot is second only to the record $656 million won by three ticket holders in March 2012.

The odds of winning were about 1 in 259 million. Twenty ticket holders won $1 million prizes.

"It was a great run," said Paula Otto, Virginia Lottery Executive Director and Lead Director for Mega Millions. He said the jackpot's 22-drawing run generated more than $300 million in profits for programs in states where tickets are sold.

If there had been no winner, the next jackpot could have surged past $825 million, easily outpacing the $656 million record jackpot split by three winners in March 2012.

The winning numbers Tuesday were 8, 20, 14, 17, 39 and 7.

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.

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.

The jackpot resets to $15 million for the next drawing, which is on Friday night.

Mega Millions lottery rival Powerball, meanwhile, has a jackpot worth $50 million. Powerball's drawing is Wednesday night.

Contributing: Jolie Lee, William Cummings; The Associated Press