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Sunday is a special day in numerous ways. It's Super Bowl Sunday, with the San Francisco 49ers taking on the Kansas City Chiefs. It's Groundhog Day, where a furry rodent tries to predict the weather. And it's an especially fun day for anyone fascinated with numbers. Sunday's date, 02-02-2020, is a palindrome, because its digits read the same forward and backwards.

There hasn't been an eight-digit palindrome like this one since 11-11-1111, 909 years ago, professor and palindrome fan Aziz Inan told The Washington Post. There was a slightly different eight-digit palindrome on Nov. 2, 2011 (11-02-2011), but while that date was a palindrome in the US, where dates are expressed as month/day/year, it didn't translate to one in countries that use the day/month/year system.

It's unlikely many people alive on Sunday will see the next palindrome of this type, which will arrive in 101 years, on 12-12-2121. But those who use the month/day/year/system will get one in that format on December 2, 2021, which is 12-02-2021.

In 2019, there was a whole Palindrome Week, beginning with 9-10-19 and continuing on through 9-19-19. But that wasn't an eight-digit palindrome -- you had to shorten the year to two digits and not use a zero in front of the month to pull that off.

Originally published Feb. 1.