166566555 has 12 divisors (see below), whose sum is σ = 288715440. Its totient is φ = 88835472.

The previous prime is 166566487. The next prime is 166566571. The reversal of 166566555 is 555665661.

It is not a de Polignac number, because 166566555 - 2²⁶ = 99457691 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 3701479 = 166566555 / (1 + 6 + 6 + 5 + 6 + 6 + 5 + 5 + 5).

It is a self number, because there is not a number n which added to its sum of digits gives 166566555.

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 11 ways as a sum of consecutive naturals, for example, 1850695 + ... + 1850784.

It is an arithmetic number, because the mean of its divisors is an integer number (24059620).

Almost surely, 2^166566555 is an apocalyptic number.

166566555 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

166566555 is a deficient number, since it is larger than the sum of its proper divisors (122148885).

166566555 is a wasteful number, since it uses less digits than its factorization.

166566555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3701490 (or 3701487 counting only the distinct ones).

The product of its digits is 810000, while the sum is 45.

The square root of 166566555 is about 12906.0665967598. The cubic root of 166566555 is about 550.2109989330.

The spelling of 166566555 in words is "one hundred sixty-six million, five hundred sixty-six thousand, five hundred fifty-five".