16661606665 has 16 divisors (see below), whose sum is σ = 21814706880. Its totient is φ = 12115782720.

The previous prime is 16661606659. The next prime is 16661606683. The reversal of 16661606665 is 56660616661.

16661606665 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 16661606665 - 2⁷ = 16661606537 is a prime.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 457042 + ... + 492148.

It is an arithmetic number, because the mean of its divisors is an integer number (1363419180).

Almost surely, 2^16661606665 is an apocalyptic number.

It is an amenable number.

16661606665 is a deficient number, since it is larger than the sum of its proper divisors (5153100215).

16661606665 is a wasteful number, since it uses less digits than its factorization.

16661606665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43752.

The product of its (nonzero) digits is 1399680, while the sum is 49.

It can be divided in two parts, 16661 and 606665, that added together give a palindrome (623326).

The spelling of 16661606665 in words is "sixteen billion, six hundred sixty-one million, six hundred six thousand, six hundred sixty-five".