Someone in Illinois won the $1.337 billion Mega Millions jackpot—the third-largest lottery prize in U.S. history

One lucky lottery ticket-buyer in Illinois may soon be a billionaire, following Friday night's $1.337 billion Mega Millions lottery drawing.

According to lottery officials, the winning numbers — 13, 36, 45, 57 and 67 and a gold Mega Ball of 14 — match a single ticket sold at a Speedway gas station in Des Plaines, Illinois, roughly 17 miles northwest of Chicago. The winner has yet to claim the prize, Harold Mays, director of the Illinois Department of the Lottery, said at a news conference on Saturday.

"We don't know whether or not they even know that they won a prize," Mays said. "So, I encourage everybody to check your ticket."

The jackpot ranks as the third-highest lottery prize in American history, and its winner — who likely paid around $2 for the ticket — stands to either gain $780.5 million as a cash lump sum or receive payments in an annuity over the next 30 years.

If the winner chooses the more popular lump sum option, which "Shark Tank" investor Kevin O'Leary recommends, he or she will have to account for a mandatory 24% federal tax withholding. The winner will likely also owe state income tax: If the winner lives in Illinois, the winnings will be considered taxable income at the state's 4.95% rate, and they may owe even more if they live in a state with a higher income tax rate.

That means the winner should expect to owe a minimum of almost $226 million in taxes, lowering the take-home amount to roughly $554.5 million — still a potentially life-changing sum of money.

In a statement on Saturday, Mega Millions also noted that 26 tickets earned second-tier prizes worth either $2 million or $1 million apiece, and a total of 14,391,740 tickets won some amount of money across nine different prize tiers Friday night.

If you're one of the lucky winners — especially if you're the mystery individual who hit the jackpot — experts say you should immediately take steps to protect your ticket and privacy.

"Privacy is key," Emily Irwin, senior director of advice at Wells Fargo Wealth & Investment Management, told CNBC on Friday. "That provides safety to both you and your family from scammers or other individuals who can start to prey on you."

You should then hire a team of professionals to assist you, including an experienced attorney, a financial advisor, a tax advisor and an insurance expert, as CNBC recently noted.

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