205235209 has 2 divisors, whose sum is σ = 205235210. Its totient is φ = 205235208.

The previous prime is 205235201. The next prime is 205235249. The reversal of 205235209 is 902532502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 205205625 + 29584 = 14325^2 + 172^2 .

It is a cyclic number.

It is not a de Polignac number, because 205235209 - 2³ = 205235201 is a prime.

It is not a weakly prime, because it can be changed into another prime (205235201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102617604 + 102617605.

It is an arithmetic number, because the mean of its divisors is an integer number (102617605).

Almost surely, 2^205235209 is an apocalyptic number.

It is an amenable number.

205235209 is a deficient number, since it is larger than the sum of its proper divisors (1).

205235209 is an equidigital number, since it uses as much as digits as its factorization.

205235209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5400, while the sum is 28.

The square root of 205235209 is about 14326.0325631348. The cubic root of 205235209 is about 589.8622765773.

The spelling of 205235209 in words is "two hundred five million, two hundred thirty-five thousand, two hundred nine".