644576966 has 16 divisors (see below), whose sum is σ = 1079293248. Its totient is φ = 286175400.

The previous prime is 644576929. The next prime is 644576971. The reversal of 644576966 is 669675446.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 339740 + ... + 341631.

It is an arithmetic number, because the mean of its divisors is an integer number (67455828).

Almost surely, 2^644576966 is an apocalyptic number.

644576966 is a deficient number, since it is larger than the sum of its proper divisors (434716282).

644576966 is a wasteful number, since it uses less digits than its factorization.

644576966 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 681427.

The product of its digits is 6531840, while the sum is 53.

The square root of 644576966 is about 25388.5203586188. The cubic root of 644576966 is about 863.8233261798.

The spelling of 644576966 in words is "six hundred forty-four million, five hundred seventy-six thousand, nine hundred sixty-six".