12656921 has 4 divisors (see below), whose sum is σ = 12951312. Its totient is φ = 12362532.

The previous prime is 12656899. The next prime is 12656927. The reversal of 12656921 is 12965621.

It is a happy number.

12656921 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12965621 = 281 ⋅46141.

It is a cyclic number.

It is not a de Polignac number, because 12656921 - 2¹⁰ = 12655897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12656927) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 147131 + ... + 147216.

It is an arithmetic number, because the mean of its divisors is an integer number (3237828).

Almost surely, 2^12656921 is an apocalyptic number.

It is an amenable number.

12656921 is a deficient number, since it is larger than the sum of its proper divisors (294391).

12656921 is an equidigital number, since it uses as much as digits as its factorization.

12656921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 294390.

The product of its digits is 6480, while the sum is 32.

The square root of 12656921 is about 3557.6566725866. The cubic root of 12656921 is about 233.0465562995.

The spelling of 12656921 in words is "twelve million, six hundred fifty-six thousand, nine hundred twenty-one".