206912309 has 2 divisors, whose sum is σ = 206912310. Its totient is φ = 206912308.

The previous prime is 206912291. The next prime is 206912311. The reversal of 206912309 is 903219602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 200307409 + 6604900 = 14153^2 + 2570^2 .

It is a cyclic number.

It is not a de Polignac number, because 206912309 - 2¹² = 206908213 is a prime.

It is a super-2 number, since 2×206912309² = 85625407231422962, which contains 22 as substring.

Together with 206912311, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (206912509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103456154 + 103456155.

It is an arithmetic number, because the mean of its divisors is an integer number (103456155).

Almost surely, 2^206912309 is an apocalyptic number.

It is an amenable number.

206912309 is a deficient number, since it is larger than the sum of its proper divisors (1).

206912309 is an equidigital number, since it uses as much as digits as its factorization.

206912309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5832, while the sum is 32.

The square root of 206912309 is about 14384.4467742072. The cubic root of 206912309 is about 591.4646260453.

The spelling of 206912309 in words is "two hundred six million, nine hundred twelve thousand, three hundred nine".