18111986 has 4 divisors (see below), whose sum is σ = 27167982. Its totient is φ = 9055992.

The previous prime is 18111949. The next prime is 18112001. The reversal of 18111986 is 68911181.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 68911181 = 1523 ⋅45247.

It can be written as a sum of positive squares in only one way, i.e., 10686361 + 7425625 = 3269^2 + 2725^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4527995 + ... + 4527998.

Almost surely, 2^18111986 is an apocalyptic number.

18111986 is a deficient number, since it is larger than the sum of its proper divisors (9055996).

18111986 is an equidigital number, since it uses as much as digits as its factorization.

18111986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9055995.

The product of its digits is 3456, while the sum is 35.

The square root of 18111986 is about 4255.8179002396. The cubic root of 18111986 is about 262.6165094291.

It can be divided in two parts, 181 and 11986, that added together give a cube (12167 = 23³).

The spelling of 18111986 in words is "eighteen million, one hundred eleven thousand, nine hundred eighty-six".