165799181 has 16 divisors (see below), whose sum is σ = 178162416. Its totient is φ = 153747456.

The previous prime is 165799163. The next prime is 165799189. The reversal of 165799181 is 181997561.

165799181 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 8 ways, for example, as 18783556 + 147015625 = 4334^2 + 12125^2 .

It is not a de Polignac number, because 165799181 - 2¹⁸ = 165537037 is a prime.

It is a super-2 number, since 2×165799181² = 54978736840541522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165799189) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 598415 + ... + 598691.

It is an arithmetic number, because the mean of its divisors is an integer number (11135151).

Almost surely, 2^165799181 is an apocalyptic number.

It is an amenable number.

165799181 is a deficient number, since it is larger than the sum of its proper divisors (12363235).

165799181 is a wasteful number, since it uses less digits than its factorization.

165799181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 688.

The product of its digits is 136080, while the sum is 47.

The square root of 165799181 is about 12876.3030796887. The cubic root of 165799181 is about 549.3647552862.

The spelling of 165799181 in words is "one hundred sixty-five million, seven hundred ninety-nine thousand, one hundred eighty-one".