638785 has 8 divisors (see below), whose sum is σ = 876096. Its totient is φ = 438000.

The previous prime is 638767. The next prime is 638801. The reversal of 638785 is 587836.

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

It is not a de Polignac number, because 638785 - 2¹³ = 630593 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9091 + ... + 9160.

It is an arithmetic number, because the mean of its divisors is an integer number (109512).

2⁶³⁸⁷⁸⁵ is an apocalyptic number.

It is an amenable number.

638785 is a deficient number, since it is larger than the sum of its proper divisors (237311).

638785 is a wasteful number, since it uses less digits than its factorization.

638785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18263.

The product of its digits is 40320, while the sum is 37.

The square root of 638785 is about 799.2402642510. The cubic root of 638785 is about 86.1228189269.

The spelling of 638785 in words is "six hundred thirty-eight thousand, seven hundred eighty-five".