6661111666 has 16 divisors (see below), whose sum is σ = 11541178080. Its totient is φ = 2849673280.

The previous prime is 6661111643. The next prime is 6661111697.

6661111666 is nontrivially palindromic in base 10.

It is a zygodrome in base 10.

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 7 ways as a sum of consecutive naturals, for example, 8904856 + ... + 8905603.

It is an arithmetic number, because the mean of its divisors is an integer number (721323630).

Almost surely, 2^6661111666 is an apocalyptic number.

6661111666 is a deficient number, since it is larger than the sum of its proper divisors (4880066414).

6661111666 is a wasteful number, since it uses less digits than its factorization.

6661111666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17810489.

The product of its digits is 46656, while the sum is 40.

The square root of 6661111666 is about 81615.6337107052. The cubic root of 6661111666 is about 1881.5491669254.

The spelling of 6661111666 in words is "six billion, six hundred sixty-one million, one hundred eleven thousand, six hundred sixty-six".