204521100 has 108 divisors (see below), whose sum is σ = 688409064. Its totient is φ = 46744320.

The previous prime is 204521099. The next prime is 204521123. The reversal of 204521100 is 1125402.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 204521100.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 7744 + ... + 21656.

It is an arithmetic number, because the mean of its divisors is an integer number (6374158).

Almost surely, 2^204521100 is an apocalyptic number.

204521100 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 204521100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (344204532).

204521100 is an abundant number, since it is smaller than the sum of its proper divisors (483887964).

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

204521100 is a wasteful number, since it uses less digits than its factorization.

204521100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13944 (or 13930 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 204521100 is about 14301.0873712456. The cubic root of 204521100 is about 589.1773462539.

Adding to 204521100 its reverse (1125402), we get a palindrome (205646502).

The spelling of 204521100 in words is "two hundred four million, five hundred twenty-one thousand, one hundred".