Eileen Murphy says the money she was ordered to pay Mike Weirsky after the divorce is now just "pocket change" for him.
The winning ticket was sold last year at a convenience store in a suburb of the South Carolina city of Greenville.
The money will be returned to participating states if not claimed in time.
The winning ticket was sold in South Carolina, the state's lottery website said.
After no winning tickets were sold for Friday night's draw.
The numbers are 15-23-53-65-70 and Mega Ball 7.
The jackpot is the second-largest in U.S. history.
The big win comes a day after a single winning Mega Millions ticket, worth $450 million, was sold in Florida.
How would you change your life If you won $970 million?
Joemel Panisa re-discovered his ticket just eight days before it was set to expire.
The jackpot is the the seventh largest in U.S. lottery history.
The odds of winning this jackpot are 1 in nearly 259 million.
The jackpot is the seventh largest in U.S. history.
Just when you thought it was safe to be a lottery winner comes the buzzkilling news that many winners, even those in the multimillion dollar range, manage to blow through their windfalls and are back to broke in under seven years.
Disappointed about missing out on the $1.6B jackpot Wednesday night? If you bought a ticket, of course you are! Chances are good, however, that you won't have to wait terribly long for another opportunity.