205865117 has 2 divisors, whose sum is σ = 205865118. Its totient is φ = 205865116.

The previous prime is 205865089. The next prime is 205865129. The reversal of 205865117 is 711568502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 194072761 + 11792356 = 13931^2 + 3434^2 .

It is a cyclic number.

It is not a de Polignac number, because 205865117 - 2⁸ = 205864861 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (205865147) 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, 102932558 + 102932559.

It is an arithmetic number, because the mean of its divisors is an integer number (102932559).

Almost surely, 2^205865117 is an apocalyptic number.

It is an amenable number.

205865117 is a deficient number, since it is larger than the sum of its proper divisors (1).

205865117 is an equidigital number, since it uses as much as digits as its factorization.

205865117 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16800, while the sum is 35.

The square root of 205865117 is about 14348.0004530248. Note that the first 3 decimals coincide. The cubic root of 205865117 is about 590.4651287648.

The spelling of 205865117 in words is "two hundred five million, eight hundred sixty-five thousand, one hundred seventeen".