204521220 has 96 divisors (see below), whose sum is σ = 673747200. Its totient is φ = 51328512.

The previous prime is 204521197. The next prime is 204521257. The reversal of 204521220 is 22125402.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 204521193 and 204521202.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1960 + ... + 20319.

It is an arithmetic number, because the mean of its divisors is an integer number (7018200).

Almost surely, 2^204521220 is an apocalyptic number.

204521220 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 204521220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (336873600).

204521220 is an abundant number, since it is smaller than the sum of its proper divisors (469225980).

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

204521220 is a wasteful number, since it uses less digits than its factorization.

204521220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22314 (or 22306 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 18.

The square root of 204521220 is about 14301.0915667301. The cubic root of 204521220 is about 589.1774614845.

Adding to 204521220 its reverse (22125402), we get a palindrome (226646622).

The spelling of 204521220 in words is "two hundred four million, five hundred twenty-one thousand, two hundred twenty".