A palindrome /ˈpælɪndroʊm/ is a word, phrase, number, or any other sequence of units which reads the same forwards as it does backwards. Examples of palindromes are the words sees, radar, madam, and aibohphobia (fear of palindromes); the sentences, “Rise to vote sir”, “Too hot to hoot”, “A war at Tarawa!”, and “Noel sees Leon”; and the numbers 44, 212, 6,776, and 12,321.
A prime number is any natural number that is greater than 1 and is divisible only by itself and 1. Examples of prime numbers are 2, 3, 5, 7, 11, and 13.
There are many palindromic prime numbers, for example, 11, 101, 373, and 10,301. Are there any four-digit prime numbers?