12564639 has 10 divisors (see below), whose sum is σ = 18769520. Its totient is φ = 8376372.

The previous prime is 12564637. The next prime is 12564667. The reversal of 12564639 is 93646521.

It is a happy number.

12564639 is a `hidden beast` number, since 1 + 2 + 5 + 646 + 3 + 9 = 666.

It is not a de Polignac number, because 12564639 - 2¹ = 12564637 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12564631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 77479 + ... + 77640.

It is an arithmetic number, because the mean of its divisors is an integer number (1876952).

Almost surely, 2^12564639 is an apocalyptic number.

12564639 is a deficient number, since it is larger than the sum of its proper divisors (6204881).

12564639 is an equidigital number, since it uses as much as digits as its factorization.

12564639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155131 (or 155122 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

The square root of 12564639 is about 3544.6634537005. The cubic root of 12564639 is about 232.4787909894.

It can be divided in two parts, 12564 and 639, that added together give a triangular number (13203 = T₁₆₂).

The spelling of 12564639 in words is "twelve million, five hundred sixty-four thousand, six hundred thirty-nine".