644670087 has 16 divisors (see below), whose sum is σ = 889872480. Its totient is φ = 414646400.

The previous prime is 644670041. The next prime is 644670109. The reversal of 644670087 is 780076446.

644670087 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 644670087 - 2⁶ = 644670023 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644670287) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 184537 + ... + 187997.

It is an arithmetic number, because the mean of its divisors is an integer number (55617030).

Almost surely, 2^644670087 is an apocalyptic number.

644670087 is a deficient number, since it is larger than the sum of its proper divisors (245202393).

644670087 is a wasteful number, since it uses less digits than its factorization.

644670087 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5634.

The product of its (nonzero) digits is 225792, while the sum is 42.

The square root of 644670087 is about 25390.3542117868. The cubic root of 644670087 is about 863.8649225667.

The spelling of 644670087 in words is "six hundred forty-four million, six hundred seventy thousand, eighty-seven".