204928021 has 4 divisors (see below), whose sum is σ = 205006432. Its totient is φ = 204849612.

The previous prime is 204927991. The next prime is 204928027. The reversal of 204928021 is 120829402.

204928021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 120829402 = 2 ⋅60414701.

It is a cyclic number.

It is not a de Polignac number, because 204928021 - 2⁷ = 204927893 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (204928027) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35145 + ... + 40558.

It is an arithmetic number, because the mean of its divisors is an integer number (51251608).

Almost surely, 2^204928021 is an apocalyptic number.

It is an amenable number.

204928021 is a deficient number, since it is larger than the sum of its proper divisors (78411).

204928021 is an equidigital number, since it uses as much as digits as its factorization.

204928021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78410.

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 204928021 is about 14315.3072268813. The cubic root of 204928021 is about 589.5678353964.

The spelling of 204928021 in words is "two hundred four million, nine hundred twenty-eight thousand, twenty-one".