12664665 has 24 divisors (see below), whose sum is σ = 23641800. Its totient is φ = 6234624.

The previous prime is 12664607. The next prime is 12664669. The reversal of 12664665 is 56646621.

It is a happy number.

12664665 is a `hidden beast` number, since 1 + 2 + 6 + 646 + 6 + 5 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 47961 + 12616704 = 219^2 + 3552^2 .

It is not a de Polignac number, because 12664665 - 2⁷ = 12664537 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (12664669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10240 + ... + 11409.

It is an arithmetic number, because the mean of its divisors is an integer number (985075).

Almost surely, 2^12664665 is an apocalyptic number.

12664665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

12664665 is a deficient number, since it is larger than the sum of its proper divisors (10977135).

12664665 is a wasteful number, since it uses less digits than its factorization.

12664665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21673 (or 21670 counting only the distinct ones).

The product of its digits is 51840, while the sum is 36.

The square root of 12664665 is about 3558.7448630100. The cubic root of 12664665 is about 233.0940756130.

The spelling of 12664665 in words is "twelve million, six hundred sixty-four thousand, six hundred sixty-five".