205813 has 8 divisors (see below), whose sum is σ = 218880. Its totient is φ = 193200.

The previous prime is 205783. The next prime is 205817. The reversal of 205813 is 318502.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 205813 - 2¹³ = 197621 is a prime.

It is a Duffinian number.

205813 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205817) 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 7 ways as a sum of consecutive naturals, for example, 1288 + ... + 1438.

It is an arithmetic number, because the mean of its divisors is an integer number (27360).

2²⁰⁵⁸¹³ is an apocalyptic number.

It is an amenable number.

205813 is a deficient number, since it is larger than the sum of its proper divisors (13067).

205813 is a wasteful number, since it uses less digits than its factorization.

205813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 227.

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 205813 is about 453.6661768305. Note that the first 3 decimals coincide. The cubic root of 205813 is about 59.0415296997.

The spelling of 205813 in words is "two hundred five thousand, eight hundred thirteen".