12656591 has 2 divisors, whose sum is σ = 12656592. Its totient is φ = 12656590.

The previous prime is 12656573. The next prime is 12656593. The reversal of 12656591 is 19565621.

It is a strong prime.

It is an emirp because it is prime and its reverse (19565621) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12656591 - 2¹⁰ = 12655567 is a prime.

Together with 12656593, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12656593) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6328295 + 6328296.

It is an arithmetic number, because the mean of its divisors is an integer number (6328296).

Almost surely, 2^12656591 is an apocalyptic number.

12656591 is a deficient number, since it is larger than the sum of its proper divisors (1).

12656591 is an equidigital number, since it uses as much as digits as its factorization.

12656591 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16200, while the sum is 35.

The square root of 12656591 is about 3557.6102934414. The cubic root of 12656591 is about 233.0445308982.

The spelling of 12656591 in words is "twelve million, six hundred fifty-six thousand, five hundred ninety-one".