18866181 has 4 divisors (see below), whose sum is σ = 25154912. Its totient is φ = 12577452.

The previous prime is 18866171. The next prime is 18866213. The reversal of 18866181 is 18166881.

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: 18166881 = 3 ⋅6055627.

It is not a de Polignac number, because 18866181 - 2⁶ = 18866117 is a prime.

It is a super-2 number, since 2×18866181² = 711865571049522, 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 (18866101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3144361 + ... + 3144366.

It is an arithmetic number, because the mean of its divisors is an integer number (6288728).

Almost surely, 2^18866181 is an apocalyptic number.

It is an amenable number.

18866181 is a deficient number, since it is larger than the sum of its proper divisors (6288731).

18866181 is an equidigital number, since it uses as much as digits as its factorization.

18866181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6288730.

The product of its digits is 18432, while the sum is 39.

The square root of 18866181 is about 4343.5217278149. The cubic root of 18866181 is about 266.2122272232.

The spelling of 18866181 in words is "eighteen million, eight hundred sixty-six thousand, one hundred eighty-one".