644031465 has 64 divisors (see below), whose sum is σ = 1289502720. Its totient is φ = 266653440.

The previous prime is 644031413. The next prime is 644031481. The reversal of 644031465 is 564130446.

644031465 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 644031465 - 2⁷ = 644031337 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 365256 + ... + 367014.

It is an arithmetic number, because the mean of its divisors is an integer number (20148480).

Almost surely, 2^644031465 is an apocalyptic number.

It is an amenable number.

644031465 is an abundant number, since it is smaller than the sum of its proper divisors (645471255).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644031465 is a wasteful number, since it uses less digits than its factorization.

644031465 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2102.

The product of its (nonzero) digits is 34560, while the sum is 33.

The square root of 644031465 is about 25377.7750206751. The cubic root of 644031465 is about 863.5795748490.

The spelling of 644031465 in words is "six hundred forty-four million, thirty-one thousand, four hundred sixty-five".