663685566 has 8 divisors (see below), whose sum is σ = 1327371144. Its totient is φ = 221228520.

The previous prime is 663685531. The next prime is 663685567. The reversal of 663685566 is 665586366.

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

663685566 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (663685567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55307125 + ... + 55307136.

It is an arithmetic number, because the mean of its divisors is an integer number (165921393).

Almost surely, 2^663685566 is an apocalyptic number.

663685566 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

663685566 is a wasteful number, since it uses less digits than its factorization.

663685566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110614266.

The product of its digits is 4665600, while the sum is 51.

The square root of 663685566 is about 25762.0955281204. The cubic root of 663685566 is about 872.2764033784.

The spelling of 663685566 in words is "six hundred sixty-three million, six hundred eighty-five thousand, five hundred sixty-six".