206684909 has 2 divisors, whose sum is σ = 206684910. Its totient is φ = 206684908.

The previous prime is 206684887. The next prime is 206684911. The reversal of 206684909 is 909486602.

206684909 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., 203632900 + 3052009 = 14270^2 + 1747^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-206684909 is a prime.

It is a Sophie Germain prime.

Together with 206684911, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 206684909.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (206684939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103342454 + 103342455.

It is an arithmetic number, because the mean of its divisors is an integer number (103342455).

Almost surely, 2^206684909 is an apocalyptic number.

It is an amenable number.

206684909 is a deficient number, since it is larger than the sum of its proper divisors (1).

206684909 is an equidigital number, since it uses as much as digits as its factorization.

206684909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 186624, while the sum is 44.

The square root of 206684909 is about 14376.5402305283. The cubic root of 206684909 is about 591.2478701984.

The spelling of 206684909 in words is "two hundred six million, six hundred eighty-four thousand, nine hundred nine".