644329064 has 32 divisors (see below), whose sum is σ = 1277472000. Its totient is φ = 303823872.

The previous prime is 644329043. The next prime is 644329067. The reversal of 644329064 is 460923446.

It is a hoax number, since the sum of its digits (38) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (38).

It is not an unprimeable number, because it can be changed into a prime (644329067) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24392 + ... + 43400.

It is an arithmetic number, because the mean of its divisors is an integer number (39921000).

Almost surely, 2^644329064 is an apocalyptic number.

It is an amenable number.

644329064 is a deficient number, since it is larger than the sum of its proper divisors (633142936).

644329064 is a wasteful number, since it uses less digits than its factorization.

644329064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19257 (or 19253 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 38.

The square root of 644329064 is about 25383.6377219657. The cubic root of 644329064 is about 863.7125708574.

The spelling of 644329064 in words is "six hundred forty-four million, three hundred twenty-nine thousand, sixty-four".