644291330 has 64 divisors (see below), whose sum is σ = 1302117120. Its totient is φ = 228096000.

The previous prime is 644291327. The next prime is 644291359. The reversal of 644291330 is 33192446.

It is a super-2 number, since 2×644291330² = 830222635826337800, which contains 22 as substring.

It is a Curzon number.

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 31 ways as a sum of consecutive naturals, for example, 487070 + ... + 488390.

It is an arithmetic number, because the mean of its divisors is an integer number (20345580).

Almost surely, 2^644291330 is an apocalyptic number.

644291330 is an abundant number, since it is smaller than the sum of its proper divisors (657825790).

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

644291330 is a wasteful number, since it uses less digits than its factorization.

644291330 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1515.

The product of its (nonzero) digits is 15552, while the sum is 32.

The square root of 644291330 is about 25382.8944370023. The cubic root of 644291330 is about 863.6957099250.

The spelling of 644291330 in words is "six hundred forty-four million, two hundred ninety-one thousand, three hundred thirty".