204857 has 2 divisors, whose sum is σ = 204858. Its totient is φ = 204856.

The previous prime is 204821. The next prime is 204859. The reversal of 204857 is 758402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 132496 + 72361 = 364^2 + 269^2 .

It is a cyclic number.

It is not a de Polignac number, because 204857 - 2⁶ = 204793 is a prime.

Together with 204859, 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 (204859) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102428 + 102429.

It is an arithmetic number, because the mean of its divisors is an integer number (102429).

2²⁰⁴⁸⁵⁷ is an apocalyptic number.

It is an amenable number.

204857 is a deficient number, since it is larger than the sum of its proper divisors (1).

204857 is an equidigital number, since it uses as much as digits as its factorization.

204857 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2240, while the sum is 26.

The square root of 204857 is about 452.6113122758. The cubic root of 204857 is about 58.9499719553.

The spelling of 204857 in words is "two hundred four thousand, eight hundred fifty-seven".