638885 has 8 divisors (see below), whose sum is σ = 825720. Its totient is φ = 471744.

The previous prime is 638861. The next prime is 638893. The reversal of 638885 is 588836.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 82369 + 556516 = 287^2 + 746^2 .

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

It is not a de Polignac number, because 638885 - 2⁸ = 638629 is a prime.

It is a congruent 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, 4850 + ... + 4979.

It is an arithmetic number, because the mean of its divisors is an integer number (103215).

2⁶³⁸⁸⁸⁵ is an apocalyptic number.

638885 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

638885 is a deficient number, since it is larger than the sum of its proper divisors (186835).

638885 is a wasteful number, since it uses less digits than its factorization.

638885 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9847.

The product of its digits is 46080, while the sum is 38.

The square root of 638885 is about 799.3028212136. The cubic root of 638885 is about 86.1273127876.

The spelling of 638885 in words is "six hundred thirty-eight thousand, eight hundred eighty-five".