644730464 has 48 divisors (see below), whose sum is σ = 1457261568. Its totient is φ = 275052672.

The previous prime is 644730461. The next prime is 644730469. The reversal of 644730464 is 464037446.

644730464 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 not an unprimeable number, because it can be changed into a prime (644730461) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 43499 + ... + 56405.

It is an arithmetic number, because the mean of its divisors is an integer number (30359616).

Almost surely, 2^644730464 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644730464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (728630784).

644730464 is an abundant number, since it is smaller than the sum of its proper divisors (812531104).

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

644730464 is a wasteful number, since it uses less digits than its factorization.

644730464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13147 (or 13139 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 38.

The square root of 644730464 is about 25391.5431590914. The cubic root of 644730464 is about 863.8918903369.

The spelling of 644730464 in words is "six hundred forty-four million, seven hundred thirty thousand, four hundred sixty-four".