204640820 has 48 divisors (see below), whose sum is σ = 454083840. Its totient is φ = 77341824.

The previous prime is 204640819. The next prime is 204640823. The reversal of 204640820 is 28046402.

It is a self number, because there is not a number n which added to its sum of digits gives 204640820.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (204640823) 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 15 ways as a sum of consecutive naturals, for example, 23507 + ... + 31013.

It is an arithmetic number, because the mean of its divisors is an integer number (9460080).

Almost surely, 2^204640820 is an apocalyptic number.

204640820 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 204640820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (227041920).

204640820 is an abundant number, since it is smaller than the sum of its proper divisors (249443020).

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

204640820 is a wasteful number, since it uses less digits than its factorization.

204640820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7592 (or 7590 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 26.

The square root of 204640820 is about 14305.2724545882. The cubic root of 204640820 is about 589.2922855815.

The spelling of 204640820 in words is "two hundred four million, six hundred forty thousand, eight hundred twenty".