644210680 has 32 divisors (see below), whose sum is σ = 1512496800. Its totient is φ = 246480256.

The previous prime is 644210639. The next prime is 644210689. The reversal of 644210680 is 86012446.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644210689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 349195 + ... + 351034.

It is an arithmetic number, because the mean of its divisors is an integer number (47265525).

Almost surely, 2^644210680 is an apocalyptic number.

It is an amenable number.

644210680 is an abundant number, since it is smaller than the sum of its proper divisors (868286120).

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

644210680 is a wasteful number, since it uses less digits than its factorization.

644210680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 700263 (or 700259 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 31.

The square root of 644210680 is about 25381.3057189736. The cubic root of 644210680 is about 863.6596703456.

The spelling of 644210680 in words is "six hundred forty-four million, two hundred ten thousand, six hundred eighty".