12640388 has 18 divisors (see below), whose sum is σ = 22465674. Its totient is φ = 6223104.

The previous prime is 12640373. The next prime is 12640393. The reversal of 12640388 is 88304621.

It can be written as a sum of positive squares in 3 ways, for example, as 3104644 + 9535744 = 1762^2 + 3088^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 21020 + ... + 21612.

It is an arithmetic number, because the mean of its divisors is an integer number (1248093).

Almost surely, 2^12640388 is an apocalyptic number.

It is an amenable number.

12640388 is a deficient number, since it is larger than the sum of its proper divisors (9825286).

12640388 is an equidigital number, since it uses as much as digits as its factorization.

12640388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 743 (or 668 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 32.

The square root of 12640388 is about 3555.3323332707. The cubic root of 12640388 is about 232.9450403630.

The spelling of 12640388 in words is "twelve million, six hundred forty thousand, three hundred eighty-eight".