165666113 has 4 divisors (see below), whose sum is σ = 167527620. Its totient is φ = 163804608.

The previous prime is 165666089. The next prime is 165666119. The reversal of 165666113 is 311666561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 311666561 = 2239 ⋅139199.

It can be written as a sum of positive squares in 2 ways, for example, as 95491984 + 70174129 = 9772^2 + 8377^2 .

It is a cyclic number.

It is not a de Polignac number, because 165666113 - 2¹⁶ = 165600577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165666119) 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, 930620 + ... + 930797.

It is an arithmetic number, because the mean of its divisors is an integer number (41881905).

Almost surely, 2^165666113 is an apocalyptic number.

It is an amenable number.

165666113 is a deficient number, since it is larger than the sum of its proper divisors (1861507).

165666113 is an equidigital number, since it uses as much as digits as its factorization.

165666113 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1861506.

The product of its digits is 19440, while the sum is 35.

The square root of 165666113 is about 12871.1348761483. The cubic root of 165666113 is about 549.2177452414.

The spelling of 165666113 in words is "one hundred sixty-five million, six hundred sixty-six thousand, one hundred thirteen".