638873785 has 8 divisors (see below), whose sum is σ = 836343936. Its totient is φ = 464635440.

The previous prime is 638873749. The next prime is 638873797. The reversal of 638873785 is 587378836.

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

It is not a de Polignac number, because 638873785 - 2⁹ = 638873273 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (55), and also a Moran number because the ratio is a prime number: 11615887 = 638873785 / (6 + 3 + 8 + 8 + 7 + 3 + 7 + 8 + 5).

It is a Duffinian number.

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 7 ways as a sum of consecutive naturals, for example, 5807889 + ... + 5807998.

It is an arithmetic number, because the mean of its divisors is an integer number (104542992).

Almost surely, 2^638873785 is an apocalyptic number.

It is an amenable number.

638873785 is a deficient number, since it is larger than the sum of its proper divisors (197470151).

638873785 is a wasteful number, since it uses less digits than its factorization.

638873785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11615903.

The product of its digits is 6773760, while the sum is 55.

The square root of 638873785 is about 25275.9527021238. The cubic root of 638873785 is about 861.2680882448.

The spelling of 638873785 in words is "six hundred thirty-eight million, eight hundred seventy-three thousand, seven hundred eighty-five".