205688 has 16 divisors (see below), whose sum is σ = 440880. Its totient is φ = 88128.

The previous prime is 205663. The next prime is 205703. The reversal of 205688 is 886502.

It is a happy number.

205688 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 205688.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1781 + ... + 1892.

It is an arithmetic number, because the mean of its divisors is an integer number (27555).

2²⁰⁵⁶⁸⁸ is an apocalyptic number.

205688 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

205688 is an abundant number, since it is smaller than the sum of its proper divisors (235192).

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

205688 is a wasteful number, since it uses less digits than its factorization.

205688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3686 (or 3682 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 29.

The square root of 205688 is about 453.5283894091. The cubic root of 205688 is about 59.0295743716.

The spelling of 205688 in words is "two hundred five thousand, six hundred eighty-eight".