206909 has 2 divisors, whose sum is σ = 206910. Its totient is φ = 206908.

The previous prime is 206897. The next prime is 206911. The reversal of 206909 is 909602.

206909 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., 168100 + 38809 = 410^2 + 197^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-206909 is a prime.

It is a super-2 number, since 2×206909² = 85622668562, which contains 22 as substring.

Together with 206911, it forms a pair of twin primes.

It is a Chen prime.

It is equal to p₁₈₅₃₉ and since 206909 and 18539 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (206939) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103454 + 103455.

It is an arithmetic number, because the mean of its divisors is an integer number (103455).

2²⁰⁶⁹⁰⁹ is an apocalyptic number.

It is an amenable number.

206909 is a deficient number, since it is larger than the sum of its proper divisors (1).

206909 is an equidigital number, since it uses as much as digits as its factorization.

206909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 972, while the sum is 26.

The square root of 206909 is about 454.8725096112. The cubic root of 206909 is about 59.1461473072.

The spelling of 206909 in words is "two hundred six thousand, nine hundred nine".