644749016 has 32 divisors (see below), whose sum is σ = 1230873600. Its totient is φ = 316535040.

The previous prime is 644748931. The next prime is 644749031. The reversal of 644749016 is 610947446.

644749016 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 503465 + ... + 504743.

It is an arithmetic number, because the mean of its divisors is an integer number (38464800).

Almost surely, 2^644749016 is an apocalyptic number.

It is an amenable number.

644749016 is a deficient number, since it is larger than the sum of its proper divisors (586124584).

644749016 is a wasteful number, since it uses less digits than its factorization.

644749016 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2379 (or 2375 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 41.

The square root of 644749016 is about 25391.9084749453. The cubic root of 644749016 is about 863.9001763673.

The spelling of 644749016 in words is "six hundred forty-four million, seven hundred forty-nine thousand, sixteen".