644747330 has 32 divisors (see below), whose sum is σ = 1230465600. Its totient is φ = 242557632.

The previous prime is 644747309. The next prime is 644747333. The reversal of 644747330 is 33747446.

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 (644747333) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14204 + ... + 38616.

It is an arithmetic number, because the mean of its divisors is an integer number (38452050).

Almost surely, 2^644747330 is an apocalyptic number.

644747330 is a deficient number, since it is larger than the sum of its proper divisors (585718270).

644747330 is a wasteful number, since it uses less digits than its factorization.

644747330 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24578.

The product of its (nonzero) digits is 169344, while the sum is 38.

The square root of 644747330 is about 25391.8752753711. The cubic root of 644747330 is about 863.8994233419.

The spelling of 644747330 in words is "six hundred forty-four million, seven hundred forty-seven thousand, three hundred thirty".