644526652 has 48 divisors (see below), whose sum is σ = 1420231680. Its totient is φ = 248616000.

The previous prime is 644526637. The next prime is 644526703. The reversal of 644526652 is 256625446.

644526652 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 15 ways as a sum of consecutive naturals, for example, 20749 + ... + 41467.

It is an arithmetic number, because the mean of its divisors is an integer number (29588160).

Almost surely, 2^644526652 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 644526652, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (710115840).

644526652 is an abundant number, since it is smaller than the sum of its proper divisors (775705028).

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

644526652 is a wasteful number, since it uses less digits than its factorization.

644526652 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20842 (or 20840 counting only the distinct ones).

The product of its digits is 345600, while the sum is 40.

The square root of 644526652 is about 25387.5294583778. The cubic root of 644526652 is about 863.8008496616.

The spelling of 644526652 in words is "six hundred forty-four million, five hundred twenty-six thousand, six hundred fifty-two".