205091017 has 2 divisors, whose sum is σ = 205091018. Its totient is φ = 205091016.

The previous prime is 205090999. The next prime is 205091099. The reversal of 205091017 is 710190502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 202094656 + 2996361 = 14216^2 + 1731^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-205091017 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 205090982 and 205091000.

It is not a weakly prime, because it can be changed into another prime (205095017) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102545508 + 102545509.

It is an arithmetic number, because the mean of its divisors is an integer number (102545509).

Almost surely, 2^205091017 is an apocalyptic number.

It is an amenable number.

205091017 is a deficient number, since it is larger than the sum of its proper divisors (1).

205091017 is an equidigital number, since it uses as much as digits as its factorization.

205091017 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 630, while the sum is 25.

The square root of 205091017 is about 14320.9991620697. Note that the first 3 decimals coincide. The cubic root of 205091017 is about 589.7241044638.

The spelling of 205091017 in words is "two hundred five million, ninety-one thousand, seventeen".