205011689 has 2 divisors, whose sum is σ = 205011690. Its totient is φ = 205011688.

The previous prime is 205011661. The next prime is 205011707. The reversal of 205011689 is 986110502.

205011689 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., 105411289 + 99600400 = 10267^2 + 9980^2 .

It is a cyclic number.

It is not a de Polignac number, because 205011689 - 2²⁰ = 203963113 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (205011629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102505844 + 102505845.

It is an arithmetic number, because the mean of its divisors is an integer number (102505845).

Almost surely, 2^205011689 is an apocalyptic number.

It is an amenable number.

205011689 is a deficient number, since it is larger than the sum of its proper divisors (1).

205011689 is an equidigital number, since it uses as much as digits as its factorization.

205011689 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4320, while the sum is 32.

The square root of 205011689 is about 14318.2292550441. The cubic root of 205011689 is about 589.6480607193.

The spelling of 205011689 in words is "two hundred five million, eleven thousand, six hundred eighty-nine".