644604465 has 16 divisors (see below), whose sum is σ = 1032490368. Its totient is φ = 343414656.

The previous prime is 644604461. The next prime is 644604473. The reversal of 644604465 is 564406446.

644604465 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 644604465 - 2² = 644604461 is a prime.

It is not an unprimeable number, because it can be changed into a prime (644604461) 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, 8877 + ... + 36986.

It is an arithmetic number, because the mean of its divisors is an integer number (64530648).

Almost surely, 2^644604465 is an apocalyptic number.

It is an amenable number.

644604465 is a deficient number, since it is larger than the sum of its proper divisors (387885903).

644604465 is a wasteful number, since it uses less digits than its factorization.

644604465 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46808.

The product of its (nonzero) digits is 276480, while the sum is 39.

The square root of 644604465 is about 25389.0619165025. The cubic root of 644604465 is about 863.8356101744.

The spelling of 644604465 in words is "six hundred forty-four million, six hundred four thousand, four hundred sixty-five".