This number is a prime.
The only 5-digit palindromic prime that is undulating and the sum of 3 consecutive primes (31643 + 31649 + 31657). Note that by adding 3 consecutive primes we only get one other undulating palindrome (16161), which is a non-prime. [Trotter]
A palindromic prime that can be expressed as a sum of powers with the four prime digits as bases and exponents (2^3 + 3^2 + 5^7 + 7^5). [Silva]
Replacing each digit by its square root, or subtracting 2 from each digit, you will have two other palindromic primes formed from prime digits (32323, 72727). [Silva]
The largest 5-digit palindromic prime whose digits are perfect squares. Coincidentally, it is the ZIP Code of Novato, California. [Silva]
Printed from the PrimePages <t5k.org> © G. L. Honaker and Chris K. Caldwell