12639805 has 4 divisors (see below), whose sum is σ = 15167772. Its totient is φ = 10111840.

The previous prime is 12639793. The next prime is 12639817. The reversal of 12639805 is 50893621.

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

It is an interprime number because it is at equal distance from previous prime (12639793) and next prime (12639817).

It can be written as a sum of positive squares in 2 ways, for example, as 5659641 + 6980164 = 2379^2 + 2642^2 .

It is not a de Polignac number, because 12639805 - 2¹⁷ = 12508733 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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, 1263976 + ... + 1263985.

It is an arithmetic number, because the mean of its divisors is an integer number (3791943).

Almost surely, 2^12639805 is an apocalyptic number.

It is an amenable number.

12639805 is a deficient number, since it is larger than the sum of its proper divisors (2527967).

12639805 is an equidigital number, since it uses as much as digits as its factorization.

12639805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2527966.

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 12639805 is about 3555.2503428029. The cubic root of 12639805 is about 232.9414590107.

The spelling of 12639805 in words is "twelve million, six hundred thirty-nine thousand, eight hundred five".