206400209 has 2 divisors, whose sum is σ = 206400210. Its totient is φ = 206400208.

The previous prime is 206400157. The next prime is 206400241. The reversal of 206400209 is 902004602.

206400209 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., 182115025 + 24285184 = 13495^2 + 4928^2 .

It is a cyclic number.

It is not a de Polignac number, because 206400209 - 2²⁰ = 205351633 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (206400269) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103200104 + 103200105.

It is an arithmetic number, because the mean of its divisors is an integer number (103200105).

Almost surely, 2^206400209 is an apocalyptic number.

It is an amenable number.

206400209 is a deficient number, since it is larger than the sum of its proper divisors (1).

206400209 is an equidigital number, since it uses as much as digits as its factorization.

206400209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 206400209 is about 14366.6352706540. The cubic root of 206400209 is about 590.9762722104.

The spelling of 206400209 in words is "two hundred six million, four hundred thousand, two hundred nine".