12978665 has 16 divisors (see below), whose sum is σ = 18094080. Its totient is φ = 8752320.

The previous prime is 12978659. The next prime is 12978683. The reversal of 12978665 is 56687921.

12978665 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 12978665 - 2⁸ = 12978409 is a prime.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 905 + ... + 5174.

It is an arithmetic number, because the mean of its divisors is an integer number (1130880).

Almost surely, 2^12978665 is an apocalyptic number.

It is an amenable number.

12978665 is a deficient number, since it is larger than the sum of its proper divisors (5115415).

12978665 is an equidigital number, since it uses as much as digits as its factorization.

12978665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6152.

The product of its digits is 181440, while the sum is 44.

The square root of 12978665 is about 3602.5914284026. The cubic root of 12978665 is about 235.0047682751.

The spelling of 12978665 in words is "twelve million, nine hundred seventy-eight thousand, six hundred sixty-five".