204845 has 8 divisors (see below), whose sum is σ = 250776. Its totient is φ = 160576.

The previous prime is 204821. The next prime is 204857. The reversal of 204845 is 548402.

It can be written as a sum of positive squares in 4 ways, for example, as 5929 + 198916 = 77^2 + 446^2 .

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 204845 - 2⁶ = 204781 is a prime.

It is a super-2 number, since 2×204845² = 83922948050, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 204845.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 122 + ... + 651.

It is an arithmetic number, because the mean of its divisors is an integer number (31347).

2²⁰⁴⁸⁴⁵ is an apocalyptic number.

It is an amenable number.

204845 is a deficient number, since it is larger than the sum of its proper divisors (45931).

204845 is an equidigital number, since it uses as much as digits as its factorization.

204845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 831.

The product of its (nonzero) digits is 1280, while the sum is 23.

The square root of 204845 is about 452.5980556741. The cubic root of 204845 is about 58.9488208865.

The spelling of 204845 in words is "two hundred four thousand, eight hundred forty-five".