205914809 has 2 divisors, whose sum is σ = 205914810. Its totient is φ = 205914808.

The previous prime is 205914749. The next prime is 205914811. The reversal of 205914809 is 908419502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 205836409 + 78400 = 14347^2 + 280^2 .

It is a cyclic number.

It is not a de Polignac number, because 205914809 - 2²⁴ = 189137593 is a prime.

Together with 205914811, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (205914899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102957404 + 102957405.

It is an arithmetic number, because the mean of its divisors is an integer number (102957405).

Almost surely, 2^205914809 is an apocalyptic number.

It is an amenable number.

205914809 is a deficient number, since it is larger than the sum of its proper divisors (1).

205914809 is an equidigital number, since it uses as much as digits as its factorization.

205914809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25920, while the sum is 38.

The square root of 205914809 is about 14349.7320184037. The cubic root of 205914809 is about 590.5126340329.

The spelling of 205914809 in words is "two hundred five million, nine hundred fourteen thousand, eight hundred nine".