Palindromic prime

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A palindromical prime number is a prime number that reads the same when reversed.

Palindromical prime numbers include:

2, 3, 5, 7, 11, 101, 131, 151, 181, 191, 313, 353, 373, 383, 727, 757, 787, 797, 919, 929, 10301, 10501, 10601, 11311, 11411, 12421, 12721, 12821, 13331, 13831, 13931, 14341, 14741, 15451, 15551, 16061, 16361, 16561, 16661, 17471, 17971, 18181, 18481, 19391, 19891, and 19991.

Out of the above list, 2 is the only number that is not an odd number. Almost all palindromic numbers are composite, for any base.

11 is the only palindromic prime with an even number of digits because all palindromic numbers with an even number of digits can be divided by 11, which means they are not primes.

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