644376730 has 16 divisors (see below), whose sum is σ = 1166361120. Its totient is φ = 256310032.

The previous prime is 644376727. The next prime is 644376739. The reversal of 644376730 is 37673446.

It is not an unprimeable number, because it can be changed into a prime (644376739) by changing a digit.

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, 178204 + ... + 181783.

It is an arithmetic number, because the mean of its divisors is an integer number (72897570).

Almost surely, 2^644376730 is an apocalyptic number.

644376730 is a deficient number, since it is larger than the sum of its proper divisors (521984390).

644376730 is a wasteful number, since it uses less digits than its factorization.

644376730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 360173.

The product of its (nonzero) digits is 254016, while the sum is 40.

The square root of 644376730 is about 25384.5766165205. The cubic root of 644376730 is about 863.7338688300.

The spelling of 644376730 in words is "six hundred forty-four million, three hundred seventy-six thousand, seven hundred thirty".