Draws take place every Tuesday and Friday at about 11 p.m. ET.
If there is a winner, he or she can take the money in a lump sum or receive 26 annual annuity-type payments.
The lump sum is worth about $40 million after taxes, according to lottery officials.
As an annuity, the jackpot is worth about $2.1 million per year minus taxes.
Lottery tickets are $1 each and available in 42 states plus the District of Columbia and the U.S. Virgin Islands.
For a national interactive map of lottery ticket sellers, visit the national Mega Millions website.
"Players may pick six numbers from two separate pools of numbers - five different numbers from 1 to 56 and one number from 1 to 46 - or select Easy Pick," according to lottery rules. "You win the jackpot by matching all six winning numbers in a drawing."
In addition to the jackpot, there are prizes ranging from $2 to $250,000.