205693 has 4 divisors (see below), whose sum is σ = 209628. Its totient is φ = 201760.

The previous prime is 205663. The next prime is 205703. The reversal of 205693 is 396502.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 396502 = 2 ⋅198251.

It can be written as a sum of positive squares in 2 ways, for example, as 139129 + 66564 = 373^2 + 258^2 .

It is a cyclic number.

It is not a de Polignac number, because 205693 - 2⁵ = 205661 is a prime.

It is a super-2 number, since 2×205693² = 84619220498, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205603) 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, 1888 + ... + 1993.

It is an arithmetic number, because the mean of its divisors is an integer number (52407).

2²⁰⁵⁶⁹³ is an apocalyptic number.

It is an amenable number.

205693 is a deficient number, since it is larger than the sum of its proper divisors (3935).

205693 is an equidigital number, since it uses as much as digits as its factorization.

205693 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3934.

The product of its (nonzero) digits is 1620, while the sum is 25.

The square root of 205693 is about 453.5339017097. The cubic root of 205693 is about 59.0300526777.

It can be divided in two parts, 205 and 693, that added together give a palindrome (898).

The spelling of 205693 in words is "two hundred five thousand, six hundred ninety-three".