Does it read the same forwards and backwards?
A palindrome is a word, phrase, number, or sequence that reads the same forward and backward. Famous examples include "racecar", "level", "civic", and the phrase "A man, a plan, a canal: Panama".
The word palindrome comes from the Greek words "palin" (again) and "dromos" (direction or way).
Single words: racecar, level, civic, radar, madam, rotor, refer. Phrases: "Was it a car or a cat I saw", "Never odd or even", "Do geese see God".
Yes — numbers like 121, 1331, and 12321 are palindromes. This checker works on numbers too.