644786532 has 36 divisors (see below), whose sum is σ = 1755253500. Its totient is φ = 198395712.

The previous prime is 644786521. The next prime is 644786533. The reversal of 644786532 is 235687446.

644786532 is a `hidden beast` number, since 6 + 44 + 78 + 6 + 532 = 666.

644786532 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 196448256 + 448338276 = 14016^2 + 21174^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is not an unprimeable number, because it can be changed into a prime (644786533) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 688407 + ... + 689342.

Almost surely, 2^644786532 is an apocalyptic number.

It is an amenable number.

644786532 is an abundant number, since it is smaller than the sum of its proper divisors (1110466968).

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

644786532 is a wasteful number, since it uses less digits than its factorization.

644786532 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1377772 (or 1377767 counting only the distinct ones).

The product of its digits is 967680, while the sum is 45.

The square root of 644786532 is about 25392.6472034721. The cubic root of 644786532 is about 863.9169319572.

The spelling of 644786532 in words is "six hundred forty-four million, seven hundred eighty-six thousand, five hundred thirty-two".