166585935891 has 4 divisors (see below), whose sum is σ = 222114581192. Its totient is φ = 111057290592.

The previous prime is 166585935851. The next prime is 166585935913. The reversal of 166585935891 is 198539585661.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 166585935891 - 2¹⁸ = 166585673747 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166585935851) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 27764322646 + ... + 27764322651.

It is an arithmetic number, because the mean of its divisors is an integer number (55528645298).

Almost surely, 2^166585935891 is an apocalyptic number.

166585935891 is a deficient number, since it is larger than the sum of its proper divisors (55528645301).

166585935891 is an equidigital number, since it uses as much as digits as its factorization.

166585935891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55528645300.

The product of its digits is 69984000, while the sum is 66.

The spelling of 166585935891 in words is "one hundred sixty-six billion, five hundred eighty-five million, nine hundred thirty-five thousand, eight hundred ninety-one".