644872752 has 50 divisors (see below), whose sum is σ = 1866452588. Its totient is φ = 214957152.

The previous prime is 644872751. The next prime is 644872769. The reversal of 644872752 is 257278446.

It is a happy number.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 644872698 and 644872707.

It is not an unprimeable number, because it can be changed into a prime (644872751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 247498 + ... + 250089.

Almost surely, 2^644872752 is an apocalyptic number.

It is an amenable number.

644872752 is an abundant number, since it is smaller than the sum of its proper divisors (1221579836).

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

644872752 is a wasteful number, since it uses less digits than its factorization.

644872752 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 497607 (or 497592 counting only the distinct ones).

The product of its digits is 752640, while the sum is 45.

The square root of 644872752 is about 25394.3448822764. The cubic root of 644872752 is about 863.9554375165.

The spelling of 644872752 in words is "six hundred forty-four million, eight hundred seventy-two thousand, seven hundred fifty-two".