166505505666 has 64 divisors (see below), whose sum is σ = 342603233280. Its totient is φ = 53917839360.

The previous prime is 166505505641. The next prime is 166505505671. The reversal of 166505505666 is 666505505661.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 52178131 + ... + 52181321.

It is an arithmetic number, because the mean of its divisors is an integer number (5353175520).

Almost surely, 2^166505505666 is an apocalyptic number.

166505505666 is an abundant number, since it is smaller than the sum of its proper divisors (176097727614).

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

166505505666 is a wasteful number, since it uses less digits than its factorization.

166505505666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4271.

The product of its (nonzero) digits is 4860000, while the sum is 51.

The spelling of 166505505666 in words is "one hundred sixty-six billion, five hundred five million, five hundred five thousand, six hundred sixty-six".