644983838 has 8 divisors (see below), whose sum is σ = 1000837080. Its totient is φ = 311371480.

The previous prime is 644983831. The next prime is 644983841. The reversal of 644983838 is 838389446.

644983838 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 644983838.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644983831) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5560148 + ... + 5560263.

It is an arithmetic number, because the mean of its divisors is an integer number (125104635).

Almost surely, 2^644983838 is an apocalyptic number.

644983838 is a deficient number, since it is larger than the sum of its proper divisors (355853242).

644983838 is a wasteful number, since it uses less digits than its factorization.

644983838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11120442.

The product of its digits is 3981312, while the sum is 53.

The square root of 644983838 is about 25396.5320073430. The cubic root of 644983838 is about 864.0050430876.

The spelling of 644983838 in words is "six hundred forty-four million, nine hundred eighty-three thousand, eight hundred thirty-eight".