204091 has 4 divisors (see below), whose sum is σ = 205000. Its totient is φ = 203184.

The previous prime is 204067. The next prime is 204101. The reversal of 204091 is 190402.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 204091 - 2⁵ = 204059 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (204791) 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, 160 + ... + 658.

It is an arithmetic number, because the mean of its divisors is an integer number (51250).

2²⁰⁴⁰⁹¹ is an apocalyptic number.

204091 is a deficient number, since it is larger than the sum of its proper divisors (909).

204091 is an equidigital number, since it uses as much as digits as its factorization.

204091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 908.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 204091 is about 451.7643190868. The cubic root of 204091 is about 58.8764050644.

Adding to 204091 its reverse (190402), we get a palindrome (394493).

Subtracting from 204091 its reverse (190402), we obtain a square (13689 = 117²).

The spelling of 204091 in words is "two hundred four thousand, ninety-one".