204021820 has 48 divisors (see below), whose sum is σ = 440596800. Its totient is φ = 79326720.

The previous prime is 204021809. The next prime is 204021821. The reversal of 204021820 is 28120402.

It is a super-2 number, since 2×204021820² = 83249806072224800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (204021821) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 107641 + ... + 109519.

It is an arithmetic number, because the mean of its divisors is an integer number (9179100).

Almost surely, 2^204021820 is an apocalyptic number.

204021820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

204021820 is an abundant number, since it is smaller than the sum of its proper divisors (236574980).

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

204021820 is a wasteful number, since it uses less digits than its factorization.

204021820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2038 (or 2036 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 19.

The square root of 204021820 is about 14283.6206894471. The cubic root of 204021820 is about 588.6975193746.

It can be divided in two parts, 20402 and 1820, that added together give a palindrome (22222).

The spelling of 204021820 in words is "two hundred four million, twenty-one thousand, eight hundred twenty".