644689330 has 32 divisors (see below), whose sum is σ = 1227115008. Its totient is φ = 243465600.

The previous prime is 644689319. The next prime is 644689387. The reversal of 644689330 is 33986446.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12652 + ... + 38071.

It is an arithmetic number, because the mean of its divisors is an integer number (38347344).

Almost surely, 2^644689330 is an apocalyptic number.

644689330 is a deficient number, since it is larger than the sum of its proper divisors (582425678).

644689330 is a wasteful number, since it uses less digits than its factorization.

644689330 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50802.

The product of its (nonzero) digits is 373248, while the sum is 43.

The square root of 644689330 is about 25390.7331520774. The cubic root of 644689330 is about 863.8735177576.

The spelling of 644689330 in words is "six hundred forty-four million, six hundred eighty-nine thousand, three hundred thirty".