204818921 has 2 divisors, whose sum is σ = 204818922. Its totient is φ = 204818920.

The previous prime is 204818897. The next prime is 204818923. The reversal of 204818921 is 129818402.

204818921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 203461696 + 1357225 = 14264^2 + 1165^2 .

It is a cyclic number.

It is not a de Polignac number, because 204818921 - 2¹⁸ = 204556777 is a prime.

Together with 204818923, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (204818923) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102409460 + 102409461.

It is an arithmetic number, because the mean of its divisors is an integer number (102409461).

Almost surely, 2^204818921 is an apocalyptic number.

It is an amenable number.

204818921 is a deficient number, since it is larger than the sum of its proper divisors (1).

204818921 is an equidigital number, since it uses as much as digits as its factorization.

204818921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9216, while the sum is 35.

The square root of 204818921 is about 14311.4961132650. The cubic root of 204818921 is about 589.4631917130.

The spelling of 204818921 in words is "two hundred four million, eight hundred eighteen thousand, nine hundred twenty-one".