18085181 has 4 divisors (see below), whose sum is σ = 18227712. Its totient is φ = 17942652.

The previous prime is 18085163. The next prime is 18085189. The reversal of 18085181 is 18158081.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 18158081 = 197 ⋅92173.

It is a cyclic number.

It is not a de Polignac number, because 18085181 - 2⁶ = 18085117 is a prime.

It is a super-2 number, since 2×18085181² = 654147543605522, 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 (18085189) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 71075 + ... + 71328.

It is an arithmetic number, because the mean of its divisors is an integer number (4556928).

Almost surely, 2^18085181 is an apocalyptic number.

It is an amenable number.

18085181 is a deficient number, since it is larger than the sum of its proper divisors (142531).

18085181 is a wasteful number, since it uses less digits than its factorization.

18085181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142530.

The product of its (nonzero) digits is 2560, while the sum is 32.

The square root of 18085181 is about 4252.6675158070. The cubic root of 18085181 is about 262.4868915601.

Subtracting 18085181 from its reverse (18158081), we obtain a square (72900 = 270²).

The spelling of 18085181 in words is "eighteen million, eighty-five thousand, one hundred eighty-one".