Topeka ? Someone who bought a golden Mega Millions ticket in northeast Kansas is now the state’s all-time jackpot winner, but lottery officials said Saturday that the person hadn’t come forward to claim a share of the $640 million prize.

“We sure want to meet the winner, but we want to tell them, sign the back of the ticket and secure it,” Dennis Wilson, the state’s lottery executive director, said during a news conference at its Topeka headquarters.

Winning tickets also were sold in Illinois and Maryland, so the Kansas ticket is worth about $213 million. The Kansas winner can take a single cash payment estimated at about $154 million.

The Kansas store that sold the ticket will get a bonus of $10,000 from the state lottery. Federal and state governments will get a small windfall in taxes, too, and lottery officials said the share for Kansas will be 5 percent, or roughly $7.7 million.

Kansas lottery ticket sales shot up thanks to the promise of a big prize. Officials estimated 3.4 million tickets were sold at the 1,850 stores offering the lottery in the three days before the drawing, with sales averaging 3,500 a minute leading up to the drawing.

The largest previous jackpot for Kansas was almost $97 million in the multistate Powerball game. It was won in November 2009 by Donald Damon, a 70-year-old retired truck driver from Great Bend, who claimed it within two days of the drawing.

Kansas law allows winners to wait up to a year to claim a prize — and remain anonymous. Wilson acknowledged that the Mega Millions winner could try to avoid being identified but said lottery officials will encourage that person to go public, so that there can be a public celebration.

But Wilson also said the person holding the ticket should secure both financial and legal help before contacting the lottery. Winners must come either to the lottery’s Topeka headquarters or its office in Great Bend to claim a prize of $600 or more.

“I would say that a lot of people are sleeping in,” Wilson said. “Hopefully, again, they’re seeking good advice before they come forward.”

Lottery officials said that while its security team may be aware of which store sold the ticket, they don’t expect to identify it or its home community until the winner comes forward. Officials said only that the winning ticket was sold in one of 21 northeast Kansas counties.