205717 has 4 divisors (see below), whose sum is σ = 217836. Its totient is φ = 193600.

The previous prime is 205703. The next prime is 205721. The reversal of 205717 is 717502.

205717 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 192721 + 12996 = 439^2 + 114^2 .

It is a cyclic number.

It is not a de Polignac number, because 205717 - 2⁷ = 205589 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205417) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6034 + ... + 6067.

It is an arithmetic number, because the mean of its divisors is an integer number (54459).

2²⁰⁵⁷¹⁷ is an apocalyptic number.

It is an amenable number.

205717 is a deficient number, since it is larger than the sum of its proper divisors (12119).

205717 is a wasteful number, since it uses less digits than its factorization.

205717 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12118.

The product of its (nonzero) digits is 490, while the sum is 22.

The square root of 205717 is about 453.5603598199. The cubic root of 205717 is about 59.0323484391.

It can be divided in two parts, 2057 and 17, that multiplied together give a square (34969 = 187²).

The spelling of 205717 in words is "two hundred five thousand, seven hundred seventeen".