18197988 has 12 divisors (see below), whose sum is σ = 42462000. Its totient is φ = 6065992.

The previous prime is 18197941. The next prime is 18198001. The reversal of 18197988 is 88979181.

It is a tau number, because it is divible by the number of its divisors (12).

It is a self number, because there is not a number n which added to its sum of digits gives 18197988.

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 in 3 ways as a sum of consecutive naturals, for example, 758238 + ... + 758261.

It is an arithmetic number, because the mean of its divisors is an integer number (3538500).

Almost surely, 2^18197988 is an apocalyptic number.

It is an amenable number.

18197988 is an abundant number, since it is smaller than the sum of its proper divisors (24264012).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18197988 is a wasteful number, since it uses less digits than its factorization.

18197988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1516506 (or 1516504 counting only the distinct ones).

The product of its digits is 290304, while the sum is 51.

The square root of 18197988 is about 4265.9099849856. The cubic root of 18197988 is about 263.0315180509.

The spelling of 18197988 in words is "eighteen million, one hundred ninety-seven thousand, nine hundred eighty-eight".