644306530 has 64 divisors (see below), whose sum is σ = 1433007360. Its totient is φ = 203606784.

The previous prime is 644306471. The next prime is 644306591. The reversal of 644306530 is 35603446.

644306530 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 644306492 and 644306501.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 42664 + ... + 55756.

It is an arithmetic number, because the mean of its divisors is an integer number (22390740).

Almost surely, 2^644306530 is an apocalyptic number.

644306530 is an abundant number, since it is smaller than the sum of its proper divisors (788700830).

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

644306530 is a wasteful number, since it uses less digits than its factorization.

644306530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13163.

The product of its (nonzero) digits is 25920, while the sum is 31.

The square root of 644306530 is about 25383.1938494745. The cubic root of 644306530 is about 863.7025019206.

Adding to 644306530 its reverse (35603446), we get a palindrome (679909976).

The spelling of 644306530 in words is "six hundred forty-four million, three hundred six thousand, five hundred thirty".