16661006665 has 8 divisors (see below), whose sum is σ = 20036959560. Its totient is φ = 13299637632.

The previous prime is 16661006657. The next prime is 16661006707. The reversal of 16661006665 is 56660016661.

It can be written as a sum of positive squares in 4 ways, for example, as 5291689536 + 11369317129 = 72744^2 + 106627^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 16661006665 - 2³ = 16661006657 is a prime.

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, 3643450 + ... + 3648019.

It is an arithmetic number, because the mean of its divisors is an integer number (2504619945).

Almost surely, 2^16661006665 is an apocalyptic number.

It is an amenable number.

16661006665 is a deficient number, since it is larger than the sum of its proper divisors (3375952895).

16661006665 is an equidigital number, since it uses as much as digits as its factorization.

16661006665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7291931.

The product of its (nonzero) digits is 233280, while the sum is 43.

The spelling of 16661006665 in words is "sixteen billion, six hundred sixty-one million, six thousand, six hundred sixty-five".