644502066 has 32 divisors (see below), whose sum is σ = 1405743360. Its totient is φ = 195796224.

The previous prime is 644502049. The next prime is 644502071. The reversal of 644502066 is 660205446.

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 15 ways as a sum of consecutive naturals, for example, 46135 + ... + 58458.

It is an arithmetic number, because the mean of its divisors is an integer number (43929480).

Almost surely, 2^644502066 is an apocalyptic number.

644502066 is an abundant number, since it is smaller than the sum of its proper divisors (761241294).

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

644502066 is a wasteful number, since it uses less digits than its factorization.

644502066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104690.

The product of its (nonzero) digits is 34560, while the sum is 33.

The square root of 644502066 is about 25387.0452396493. The cubic root of 644502066 is about 863.7898660570.

The spelling of 644502066 in words is "six hundred forty-four million, five hundred two thousand, sixty-six".