The payout jumped nearly $200 million due to brisk ticket sales after no one won the top prize in Saturday's drawing, said Mary Neubauer, a spokeswoman for the Iowa Lottery, where Powerball is based.
The next drawing will be held on Wednesday night. Powerball has not had a winner for two months.
The potential windfall has drawn interest from around the world, Neubauer said. Lottery officials have received calls and emails from people outside the United States asking if they can buy a ticket from afar.
"No, that's not possible," said Neubauer, adding tickets must be purchased in one of the participating 42 states, the District of Columbia or the U.S. Virgin Islands.
The previous top Powerball prize of $365 million was won in 2006 by ConAgra slaughterhouse workers in Nebraska.
In March, three winning tickets — including one purchased by three Baltimore County public school educators — shared the largest U.S. lottery jackpot, the $656 million Mega Millions drawing.