644323464 has 32 divisors (see below), whose sum is σ = 1789788000. Its totient is φ = 214774416.

The previous prime is 644323453. The next prime is 644323543. The reversal of 644323464 is 464323446.

644323464 is a `hidden beast` number, since 644 + 3 + 2 + 3 + 4 + 6 + 4 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1491274 + ... + 1491705.

It is an arithmetic number, because the mean of its divisors is an integer number (55930875).

Almost surely, 2^644323464 is an apocalyptic number.

It is an amenable number.

644323464 is an abundant number, since it is smaller than the sum of its proper divisors (1145464536).

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

644323464 is a wasteful number, since it uses less digits than its factorization.

644323464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2982994 (or 2982984 counting only the distinct ones).

The product of its digits is 165888, while the sum is 36.

The square root of 644323464 is about 25383.5274144473. The cubic root of 644323464 is about 863.7100686140.

It can be divided in two parts, 64432 and 3464, that added together give a triangular number (67896 = T₃₆₈).

The spelling of 644323464 in words is "six hundred forty-four million, three hundred twenty-three thousand, four hundred sixty-four".