206665 has 4 divisors (see below), whose sum is σ = 248004. Its totient is φ = 165328.

The previous prime is 206651. The next prime is 206699. The reversal of 206665 is 566602.

206665 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 145161 + 61504 = 381^2 + 248^2 .

It is a cyclic number.

It is not a de Polignac number, because 206665 - 2⁹ = 206153 is a prime.

It is a Duffinian 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, 20662 + ... + 20671.

It is an arithmetic number, because the mean of its divisors is an integer number (62001).

2²⁰⁶⁶⁶⁵ is an apocalyptic number.

It is an amenable number.

206665 is a deficient number, since it is larger than the sum of its proper divisors (41339).

206665 is an equidigital number, since it uses as much as digits as its factorization.

206665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41338.

The product of its (nonzero) digits is 2160, while the sum is 25.

The square root of 206665 is about 454.6042234736. The cubic root of 206665 is about 59.1228885533.

The spelling of 206665 in words is "two hundred six thousand, six hundred sixty-five".