206563664665 has 16 divisors (see below), whose sum is σ = 254043098496. Its totient is φ = 161151984000.

The previous prime is 206563664641. The next prime is 206563664689. The reversal of 206563664665 is 566466365602.

It is an interprime number because it is at equal distance from previous prime (206563664641) and next prime (206563664689).

It is not a de Polignac number, because 206563664665 - 2⁷ = 206563664537 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 625636 + ... + 896965.

It is an arithmetic number, because the mean of its divisors is an integer number (15877693656).

Almost surely, 2^206563664665 is an apocalyptic number.

It is an amenable number.

206563664665 is a deficient number, since it is larger than the sum of its proper divisors (47479433831).

206563664665 is a wasteful number, since it uses less digits than its factorization.

206563664665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1523280.

The product of its (nonzero) digits is 27993600, while the sum is 55.

The spelling of 206563664665 in words is "two hundred six billion, five hundred sixty-three million, six hundred sixty-four thousand, six hundred sixty-five".