205818 has 8 divisors (see below), whose sum is σ = 411648. Its totient is φ = 68604.

The previous prime is 205817. The next prime is 205823. The reversal of 205818 is 818502.

205818 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

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

205818 is an admirable number.

It is a super-2 number, since 2×205818² = 84722098248, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (205817) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 17146 + ... + 17157.

It is an arithmetic number, because the mean of its divisors is an integer number (51456).

2²⁰⁵⁸¹⁸ is an apocalyptic number.

205818 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.

205818 is a wasteful number, since it uses less digits than its factorization.

205818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34308.

The product of its (nonzero) digits is 640, while the sum is 24.

The square root of 205818 is about 453.6716874569. The cubic root of 205818 is about 59.0420078121.

The spelling of 205818 in words is "two hundred five thousand, eight hundred eighteen".