205657 has 2 divisors, whose sum is σ = 205658. Its totient is φ = 205656.

The previous prime is 205651. The next prime is 205661. The reversal of 205657 is 756502.

It is a happy number.

205657 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., 156816 + 48841 = 396^2 + 221^2 .

It is a cyclic number.

It is not a de Polignac number, because 205657 - 2⁷ = 205529 is a prime.

It is not a weakly prime, because it can be changed into another prime (205651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102828 + 102829.

It is an arithmetic number, because the mean of its divisors is an integer number (102829).

2²⁰⁵⁶⁵⁷ is an apocalyptic number.

It is an amenable number.

205657 is a deficient number, since it is larger than the sum of its proper divisors (1).

205657 is an equidigital number, since it uses as much as digits as its factorization.

205657 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2100, while the sum is 25.

The square root of 205657 is about 453.4942116499. The cubic root of 205657 is about 59.0266087007.

The spelling of 205657 in words is "two hundred five thousand, six hundred fifty-seven".