205665 has 8 divisors (see below), whose sum is σ = 329088. Its totient is φ = 109680.

The previous prime is 205663. The next prime is 205703. The reversal of 205665 is 566502.

205665 is nontrivially palindromic in base 14.

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

It is not a de Polignac number, because 205665 - 2¹ = 205663 is a prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 205665.

It is not an unprimeable number, because it can be changed into a prime (205661) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6841 + ... + 6870.

It is an arithmetic number, because the mean of its divisors is an integer number (41136).

2²⁰⁵⁶⁶⁵ is an apocalyptic number.

It is an amenable number.

205665 is a deficient number, since it is larger than the sum of its proper divisors (123423).

205665 is a wasteful number, since it uses less digits than its factorization.

205665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13719.

The product of its (nonzero) digits is 1800, while the sum is 24.

The square root of 205665 is about 453.5030319634. The cubic root of 205665 is about 59.0273740636.

The spelling of 205665 in words is "two hundred five thousand, six hundred sixty-five".