18152181 has 10 divisors (see below), whose sum is σ = 27116342. Its totient is φ = 12101400.

The previous prime is 18152179. The next prime is 18152191. The reversal of 18152181 is 18125181.

It can be written as a sum of positive squares in only one way, i.e., 16329681 + 1822500 = 4041^2 + 1350^2 .

It is not a de Polignac number, because 18152181 - 2¹ = 18152179 is a prime.

It is a super-2 number, since 2×18152181² = 659003350113522, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18152111) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 111970 + ... + 112131.

Almost surely, 2^18152181 is an apocalyptic number.

It is an amenable number.

18152181 is a deficient number, since it is larger than the sum of its proper divisors (8964161).

18152181 is an equidigital number, since it uses as much as digits as its factorization.

18152181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 224113 (or 224104 counting only the distinct ones).

The product of its digits is 640, while the sum is 27.

The square root of 18152181 is about 4260.5376421292. The cubic root of 18152181 is about 262.8106363369.

Subtracting from 18152181 its reverse (18125181), we obtain a cube (27000 = 30³).

The spelling of 18152181 in words is "eighteen million, one hundred fifty-two thousand, one hundred eighty-one".