204505 has 8 divisors (see below), whose sum is σ = 280512. Its totient is φ = 140208.

The previous prime is 204487. The next prime is 204509. The reversal of 204505 is 505402.

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 204505 - 2⁷ = 204377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (204509) 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, 2887 + ... + 2956.

It is an arithmetic number, because the mean of its divisors is an integer number (35064).

2²⁰⁴⁵⁰⁵ is an apocalyptic number.

It is an amenable number.

204505 is a deficient number, since it is larger than the sum of its proper divisors (76007).

204505 is an equidigital number, since it uses as much as digits as its factorization.

204505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5855.

The product of its (nonzero) digits is 200, while the sum is 16.

The square root of 204505 is about 452.2222904723. Note that the first 4 decimals coincide. The cubic root of 204505 is about 58.9161885740.

Adding to 204505 its reverse (505402), we get a palindrome (709907).

It can be divided in two parts, 20 and 4505, that multiplied together give a triangular number (90100 = T₄₂₄).

The spelling of 204505 in words is "two hundred four thousand, five hundred five".