204820 has 72 divisors (see below), whose sum is σ = 574560. Its totient is φ = 60480.

The previous prime is 204803. The next prime is 204821. The reversal of 204820 is 28402.

204820 = T₁₃₃ + T₁₃₄ + ... + T₁₅₂.

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 204794 and 204803.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (204821) by changing a digit.

204820 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10771 + ... + 10789.

It is an arithmetic number, because the mean of its divisors is an integer number (7980).

2²⁰⁴⁸²⁰ is an apocalyptic number.

204820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 204820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (287280).

204820 is an abundant number, since it is smaller than the sum of its proper divisors (369740).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

204820 is a wasteful number, since it uses less digits than its factorization.

204820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53 (or 44 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 204820 is about 452.5704365068. The cubic root of 204820 is about 58.9464226822.

It can be divided in two parts, 204 and 820, that added together give a 10-th power (1024 = 2¹⁰).

The spelling of 204820 in words is "two hundred four thousand, eight hundred twenty".