18109988 has 12 divisors (see below), whose sum is σ = 34130460. Its totient is φ = 8358432.

The previous prime is 18109969. The next prime is 18109999. The reversal of 18109988 is 88990181.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 12166144 + 5943844 = 3488^2 + 2438^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 174083 + ... + 174186.

It is an arithmetic number, because the mean of its divisors is an integer number (2844205).

Almost surely, 2^18109988 is an apocalyptic number.

It is an amenable number.

18109988 is a deficient number, since it is larger than the sum of its proper divisors (16020472).

18109988 is a wasteful number, since it uses less digits than its factorization.

18109988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 348286 (or 348284 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 44.

The square root of 18109988 is about 4255.5831562783. The cubic root of 18109988 is about 262.6068523419.

The spelling of 18109988 in words is "eighteen million, one hundred nine thousand, nine hundred eighty-eight".