644003138 has 8 divisors (see below), whose sum is σ = 1016847120. Its totient is φ = 305054100.

The previous prime is 644003123. The next prime is 644003141. The reversal of 644003138 is 831300446.

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 644003138.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 8473688 + ... + 8473763.

It is an arithmetic number, because the mean of its divisors is an integer number (127105890).

Almost surely, 2^644003138 is an apocalyptic number.

644003138 is a deficient number, since it is larger than the sum of its proper divisors (372843982).

644003138 is a wasteful number, since it uses less digits than its factorization.

644003138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16947472.

The product of its (nonzero) digits is 6912, while the sum is 29.

The square root of 644003138 is about 25377.2169080851. The cubic root of 644003138 is about 863.5669134711.

The spelling of 644003138 in words is "six hundred forty-four million, three thousand, one hundred thirty-eight".