204815 has 16 divisors (see below), whose sum is σ = 278208. Its totient is φ = 143616.

The previous prime is 204803. The next prime is 204821. The reversal of 204815 is 518402.

It is a cyclic number.

It is not a de Polignac number, because 204815 - 2⁶ = 204751 is a prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 204815.

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 15 ways as a sum of consecutive naturals, for example, 1427 + ... + 1563.

It is an arithmetic number, because the mean of its divisors is an integer number (17388).

2²⁰⁴⁸¹⁵ is an apocalyptic number.

204815 is a deficient number, since it is larger than the sum of its proper divisors (73393).

204815 is a wasteful number, since it uses less digits than its factorization.

204815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 178.

The product of its (nonzero) digits is 320, while the sum is 20.

The square root of 204815 is about 452.5649124711. The cubic root of 204815 is about 58.9459430179.

The spelling of 204815 in words is "two hundred four thousand, eight hundred fifteen".