638845 has 8 divisors (see below), whose sum is σ = 778464. Its totient is φ = 503184.

The previous prime is 638839. The next prime is 638857. The reversal of 638845 is 548836.

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

It is a cyclic number.

It is not a de Polignac number, because 638845 - 2⁷ = 638717 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 638845.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 619 + ... + 1288.

It is an arithmetic number, because the mean of its divisors is an integer number (97308).

2⁶³⁸⁸⁴⁵ is an apocalyptic number.

It is an amenable number.

638845 is a deficient number, since it is larger than the sum of its proper divisors (139619).

638845 is a wasteful number, since it uses less digits than its factorization.

638845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1979.

The product of its digits is 23040, while the sum is 34.

The square root of 638845 is about 799.2777990161. The cubic root of 638845 is about 86.1255152996.

Subtracting from 638845 its reverse (548836), we obtain a palindrome (90009).

The spelling of 638845 in words is "six hundred thirty-eight thousand, eight hundred forty-five".