205638 has 8 divisors (see below), whose sum is σ = 411288. Its totient is φ = 68544.

The previous prime is 205633. The next prime is 205651. The reversal of 205638 is 836502.

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

205638 is an admirable number.

It is a Smith number, since the sum of its digits (24) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205633) by changing a digit.

205638 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17131 + ... + 17142.

It is an arithmetic number, because the mean of its divisors is an integer number (51411).

2²⁰⁵⁶³⁸ is an apocalyptic number.

205638 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

205638 is a wasteful number, since it uses less digits than its factorization.

205638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34278.

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 205638 is about 453.4732627179. The cubic root of 205638 is about 59.0247908841.

The spelling of 205638 in words is "two hundred five thousand, six hundred thirty-eight".