15640641 has 8 divisors (see below), whose sum is σ = 23171360. Its totient is φ = 10427076.

The previous prime is 15640637. The next prime is 15640643. The reversal of 15640641 is 14604651.

15640641 is a `hidden beast` number, since 15 + 6 + 4 + 0 + 641 = 666.

It is not a de Polignac number, because 15640641 - 2² = 15640637 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 579283 = 15640641 / (1 + 5 + 6 + 4 + 0 + 6 + 4 + 1).

It is a Duffinian number.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (15640643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 289615 + ... + 289668.

It is an arithmetic number, because the mean of its divisors is an integer number (2896420).

Almost surely, 2^15640641 is an apocalyptic number.

It is an amenable number.

15640641 is a deficient number, since it is larger than the sum of its proper divisors (7530719).

15640641 is an equidigital number, since it uses as much as digits as its factorization.

15640641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 579292 (or 579286 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 15640641 is about 3954.8250277351. The cubic root of 15640641 is about 250.0833908474.

The spelling of 15640641 in words is "fifteen million, six hundred forty thousand, six hundred forty-one".