644835428 has 24 divisors (see below), whose sum is σ = 1135602720. Its totient is φ = 320384960.

The previous prime is 644835427. The next prime is 644835461. The reversal of 644835428 is 824538446.

644835428 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (644835427) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 632303 + ... + 633321.

It is an arithmetic number, because the mean of its divisors is an integer number (47316780).

Almost surely, 2^644835428 is an apocalyptic number.

It is an amenable number.

644835428 is a deficient number, since it is larger than the sum of its proper divisors (490767292).

644835428 is a wasteful number, since it uses less digits than its factorization.

644835428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1867 (or 1865 counting only the distinct ones).

The product of its digits is 737280, while the sum is 44.

The square root of 644835428 is about 25393.6099836160. The cubic root of 644835428 is about 863.9387691661.

The spelling of 644835428 in words is "six hundred forty-four million, eight hundred thirty-five thousand, four hundred twenty-eight".