644628852 has 72 divisors (see below), whose sum is σ = 1865013696. Its totient is φ = 183907584.

The previous prime is 644628847. The next prime is 644628857. The reversal of 644628852 is 258826446.

644628852 is a `hidden beast` number, since 64 + 462 + 88 + 52 = 666.

It is an interprime number because it is at equal distance from previous prime (644628847) and next prime (644628857).

It is a junction number, because it is equal to n+sod(n) for n = 644628798 and 644628807.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644628857) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 221068 + ... + 223964.

It is an arithmetic number, because the mean of its divisors is an integer number (25902968).

Almost surely, 2^644628852 is an apocalyptic number.

It is an amenable number.

644628852 is an abundant number, since it is smaller than the sum of its proper divisors (1220384844).

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

644628852 is a wasteful number, since it uses less digits than its factorization.

644628852 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3797 (or 3792 counting only the distinct ones).

The product of its digits is 737280, while the sum is 45.

The square root of 644628852 is about 25389.5421778338. The cubic root of 644628852 is about 863.8465037246.

The spelling of 644628852 in words is "six hundred forty-four million, six hundred twenty-eight thousand, eight hundred fifty-two".