12640279 has 4 divisors (see below), whose sum is σ = 12660120. Its totient is φ = 12620440.

The previous prime is 12640261. The next prime is 12640283. The reversal of 12640279 is 97204621.

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

It is a cyclic number.

It is not a de Polignac number, because 12640279 - 2⁵ = 12640247 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 12640279.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12640879) 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, 8932 + ... + 10249.

It is an arithmetic number, because the mean of its divisors is an integer number (3165030).

Almost surely, 2^12640279 is an apocalyptic number.

12640279 is a deficient number, since it is larger than the sum of its proper divisors (19841).

12640279 is an equidigital number, since it uses as much as digits as its factorization.

12640279 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19840.

The product of its (nonzero) digits is 6048, while the sum is 31.

The square root of 12640279 is about 3555.3170041503. The cubic root of 12640279 is about 232.9443707875.

The spelling of 12640279 in words is "twelve million, six hundred forty thousand, two hundred seventy-nine".