663566665 has 8 divisors (see below), whose sum is σ = 796421448. Its totient is φ = 530759040.

The previous prime is 663566653. The next prime is 663566671. The reversal of 663566665 is 566665366.

663566665 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 64834704 + 598731961 = 8052^2 + 24469^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 663566665 - 2¹¹ = 663564617 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 39325 + ... + 53605.

It is an arithmetic number, because the mean of its divisors is an integer number (99552681).

Almost surely, 2^663566665 is an apocalyptic number.

It is an amenable number.

663566665 is a deficient number, since it is larger than the sum of its proper divisors (132854783).

663566665 is a wasteful number, since it uses less digits than its factorization.

663566665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23579.

The product of its digits is 3499200, while the sum is 49.

The square root of 663566665 is about 25759.7877514548. The cubic root of 663566665 is about 872.2243100699.

The spelling of 663566665 in words is "six hundred sixty-three million, five hundred sixty-six thousand, six hundred sixty-five".