644004156 has 12 divisors (see below), whose sum is σ = 1502676392. Its totient is φ = 214668048.

The previous prime is 644004143. The next prime is 644004161. The reversal of 644004156 is 651400446.

644004156 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26833495 + ... + 26833518.

Almost surely, 2^644004156 is an apocalyptic number.

It is an amenable number.

644004156 is an abundant number, since it is smaller than the sum of its proper divisors (858672236).

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

644004156 is a wasteful number, since it uses less digits than its factorization.

644004156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53667020 (or 53667018 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 30.

The square root of 644004156 is about 25377.2369654381. The cubic root of 644004156 is about 863.5673684951.

The spelling of 644004156 in words is "six hundred forty-four million, four thousand, one hundred fifty-six".