205009817 has 16 divisors (see below), whose sum is σ = 222600960. Its totient is φ = 188068608.

The previous prime is 205009801. The next prime is 205009841. The reversal of 205009817 is 718900502.

It is a cyclic number.

It is not a de Polignac number, because 205009817 - 2⁴ = 205009801 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (205005817) 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 in 15 ways as a sum of consecutive naturals, for example, 302483 + ... + 303159.

It is an arithmetic number, because the mean of its divisors is an integer number (13912560).

Almost surely, 2^205009817 is an apocalyptic number.

It is an amenable number.

205009817 is a deficient number, since it is larger than the sum of its proper divisors (17591143).

205009817 is a wasteful number, since it uses less digits than its factorization.

205009817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1120.

The product of its (nonzero) digits is 5040, while the sum is 32.

The square root of 205009817 is about 14318.1638836829. The cubic root of 205009817 is about 589.6462659850.

The spelling of 205009817 in words is "two hundred five million, nine thousand, eight hundred seventeen".