12640389 has 4 divisors (see below), whose sum is σ = 16853856. Its totient is φ = 8426924.

The previous prime is 12640373. The next prime is 12640393. The reversal of 12640389 is 98304621.

12640389 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 98304621 = 3 ⋅32768207.

It is a cyclic number.

It is not a de Polignac number, because 12640389 - 2⁴ = 12640373 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12640399) 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, 2106729 + ... + 2106734.

It is an arithmetic number, because the mean of its divisors is an integer number (4213464).

Almost surely, 2^12640389 is an apocalyptic number.

It is an amenable number.

12640389 is a deficient number, since it is larger than the sum of its proper divisors (4213467).

12640389 is an equidigital number, since it uses as much as digits as its factorization.

12640389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4213466.

The product of its (nonzero) digits is 10368, while the sum is 33.

The square root of 12640389 is about 3555.3324739045. The cubic root of 12640389 is about 232.9450465058.

The spelling of 12640389 in words is "twelve million, six hundred forty thousand, three hundred eighty-nine".