The rare palindrome date also coincides with National Margarita Day in the U.S. Wedding venues, airlines, hotels, and fast-food chains are among those marking "Twosday" with limited-time deals.

Transcript

RACHEL MARTIN, HOST:

So you know, today isn't just a Tuesday, it's also Twosday - that's T-W-O-S day. Today's date is February 22, 2022. As a five-digit date, that's 2-22-22.

AZIZ INAN: The occurrence of such date is rare.

A MARTINEZ, HOST:

Aziz Inan is a professor of electrical engineering at the University of Portland. And he's also fascinated by numerical patterns.

INAN: If you write this date number in full, using all the digits of the year number in the calendar system where they put the day number before the month number, this date is going to be 22-02-2022, which is going to be another rare, eight-digit, full palindrome date. And such full dates do not repeat.

MARTINEZ: Professor Inan isn't the only one excited about this. I am, too, by the way. Today is also a very popular date for weddings around the world. And a few hotels are offering so-called 222 deals, with 22% discounts and rooms for two 22 - $222 a night. So you should plan something life-changing and try to pronounce this whole thing right, too. Depends on who you ask, though.

BARRY MARKOVSKY: There's nothing of consequence, really, associated with the date itself. Or calendar itself is kind of arbitrary. And so those dates don't necessarily signify anything on any particular day. But it is just kind of a fun thing to notice.

MARTIN: Yes, it is, Barry Markovsky. He's a professor emeritus of sociology at the University of South Carolina. He says finding meaning in today's date says more about humans' ability to find patterns more than anything else. In primitive times, he says, it was essential.

MARKOVSKY: Recognizing footprints of animals and being able to distinguish the patterns of predators versus prey makes the difference between life and death.

MARTINEZ: Still, Professor Inan at the University of Portland hopes everyone is able to mark today in some special way.

INAN: These symmetric dates have what I call magic power. It's amazing how - when you share, you know? Like, you have to wait 100 years to experience this again. And, you know, I can't imagine doing anything else but spread positive energy and make people have fun.

(SOUNDBITE OF DARUMA'S "DARUMA") Transcript provided by NPR, Copyright NPR.