13656561 has 4 divisors (see below), whose sum is σ = 18208752. Its totient is φ = 9104372.

The previous prime is 13656557. The next prime is 13656581. The reversal of 13656561 is 16565631.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 13656561 - 2² = 13656557 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (13656521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2276091 + ... + 2276096.

It is an arithmetic number, because the mean of its divisors is an integer number (4552188).

Almost surely, 2^13656561 is an apocalyptic number.

It is an amenable number.

13656561 is a deficient number, since it is larger than the sum of its proper divisors (4552191).

13656561 is an equidigital number, since it uses as much as digits as its factorization.

13656561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4552190.

The product of its digits is 16200, while the sum is 33.

The square root of 13656561 is about 3695.4784534617. The cubic root of 13656561 is about 239.0270856251.

The spelling of 13656561 in words is "thirteen million, six hundred fifty-six thousand, five hundred sixty-one".