OMAHA, Neb. -- Lottery officials say the Powerball jackpot has grown to US$1.4 billion, the largest ever in the world, and the drawing is still two days away.

The prize could grow even more before Wednesday's drawing if ticket sales remain intense. Officials review the estimate daily.

The jackpot is so big that billboards around the country have to advertise the price as $999 million because they're not built to show billions.

No one matched all six Powerball numbers Saturday night.

"We've never been at these levels," said Texas Lottery executive director Gary Grief, whose state lottery is part of the Multi-State Lottery Association that runs Powerball.

The odds to win are one in 292.2 million. Forty-four U.S. states participate.

The jackpot has ballooned since its Nov. 4 starting point of $40 million and spurred huge ticket sales.

Between Jan. 6 and Saturday's drawings, more than $900 million in Powerball tickets were sold.

"It's exponentially greater than any sales that any of the states involved have ever seen," Grief said.

A winner would have the option of being paid through annual payments over 29 years or opting for one smaller cash payment. But 39.6 per cent of the lump sum would go to federal income taxes.

Associated Press writers Terry Tang in Phoenix and Olga R. Rodriguez in San Francisco contributed to this report.