12864639 has 4 divisors (see below), whose sum is σ = 17152856. Its totient is φ = 8576424.

The previous prime is 12864623. The next prime is 12864667. The reversal of 12864639 is 93646821.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 12864639 - 2⁴ = 12864623 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 12864597 and 12864606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12864679) 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 3 ways as a sum of consecutive naturals, for example, 2144104 + ... + 2144109.

It is an arithmetic number, because the mean of its divisors is an integer number (4288214).

Almost surely, 2^12864639 is an apocalyptic number.

12864639 is a deficient number, since it is larger than the sum of its proper divisors (4288217).

12864639 is an equidigital number, since it uses as much as digits as its factorization.

12864639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4288216.

The product of its digits is 62208, while the sum is 39.

The square root of 12864639 is about 3586.7309628686. The cubic root of 12864639 is about 234.3145197189.

The spelling of 12864639 in words is "twelve million, eight hundred sixty-four thousand, six hundred thirty-nine".