206117309 has 2 divisors, whose sum is σ = 206117310. Its totient is φ = 206117308.

The previous prime is 206117273. The next prime is 206117323. The reversal of 206117309 is 903711602.

206117309 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., 205836409 + 280900 = 14347^2 + 530^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-206117309 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (206117369) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103058654 + 103058655.

It is an arithmetic number, because the mean of its divisors is an integer number (103058655).

Almost surely, 2^206117309 is an apocalyptic number.

It is an amenable number.

206117309 is a deficient number, since it is larger than the sum of its proper divisors (1).

206117309 is an equidigital number, since it uses as much as digits as its factorization.

206117309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2268, while the sum is 29.

The square root of 206117309 is about 14356.7861654341. The cubic root of 206117309 is about 590.7061438825.

The spelling of 206117309 in words is "two hundred six million, one hundred seventeen thousand, three hundred nine".