638806 has 16 divisors (see below), whose sum is σ = 1108224. Its totient is φ = 270504.

The previous prime is 638801. The next prime is 638819. The reversal of 638806 is 608836.

It is a nialpdrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638801) by changing a digit.

638806 is an untouchable number, because it is not equal to the sum of proper divisors of any 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, 1221 + ... + 1663.

It is an arithmetic number, because the mean of its divisors is an integer number (69264).

2⁶³⁸⁸⁰⁶ is an apocalyptic number.

638806 is a deficient number, since it is larger than the sum of its proper divisors (469418).

638806 is a wasteful number, since it uses less digits than its factorization.

638806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 555.

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 638806 is about 799.2534016193. The cubic root of 638806 is about 86.1237626765.

It can be divided in two parts, 638 and 806, that added together give a square (1444 = 38²).

The spelling of 638806 in words is "six hundred thirty-eight thousand, eight hundred six".