15666155666 has 16 divisors (see below), whose sum is σ = 26891208960. Its totient is φ = 6705331200.

The previous prime is 15666155651. The next prime is 15666155677. The reversal of 15666155666 is 66655166651.

It is a happy number.

It is a Smith number, since the sum of its digits (53) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon 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, 716810 + ... + 738341.

It is an arithmetic number, because the mean of its divisors is an integer number (1680700560).

Almost surely, 2^15666155666 is an apocalyptic number.

15666155666 is a deficient number, since it is larger than the sum of its proper divisors (11225053294).

15666155666 is a wasteful number, since it uses less digits than its factorization.

15666155666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1455929.

The product of its digits is 5832000, while the sum is 53.

The spelling of 15666155666 in words is "fifteen billion, six hundred sixty-six million, one hundred fifty-five thousand, six hundred sixty-six".