12640387 has 4 divisors (see below), whose sum is σ = 12665080. Its totient is φ = 12615696.

The previous prime is 12640373. The next prime is 12640393. The reversal of 12640387 is 78304621.

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 12640387 - 2¹⁵ = 12607619 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12640307) 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, 11562 + ... + 12607.

It is an arithmetic number, because the mean of its divisors is an integer number (3166270).

Almost surely, 2^12640387 is an apocalyptic number.

12640387 is a deficient number, since it is larger than the sum of its proper divisors (24693).

12640387 is an equidigital number, since it uses as much as digits as its factorization.

12640387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24692.

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 12640387 is about 3555.3321926369. The cubic root of 12640387 is about 232.9450342201.

The spelling of 12640387 in words is "twelve million, six hundred forty thousand, three hundred eighty-seven".