# Emirps

An emirp (prime spelled backwards) is a prime number that results in a different prime when its decimal digits are reversed.[1] This definition excludes the related palindromic primes. The term reversible prime may be used to mean the same as emirp, but may also, ambiguously, include the palindromic primes.

Except for 11, all palindromic primes have an odd number of digits, because the divisibility test for 11 tells us that every palindromic number with an even number of digits is a multiple of 11.

All non-palindromic permutable primes are emirps.

First 20: 13, 17, 31, 37, 71, 73, 79, 97, 107, 113, 149, 157, 167, 179, 199, 311, 337, 347, 359, 389

Checkout list of first: 10, 50, 100, 500, 1000 Emirps. You can also check all Emirps.

## Visualization#

Every frame counter is increased by one. If it is emirps then dot appears. Color has no meaning. Video has 25fps.

You can also compare it with other types.

## External#

- OEIS: A006567
- Wikipedia: Emirps
- Youtube: Visualization up to 1 million

## Tags#

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