19998618 has 8 divisors (see below), whose sum is σ = 39997248. Its totient is φ = 6666204.

The previous prime is 19998617. The next prime is 19998637. The reversal of 19998618 is 81689991.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

19998618 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (19998617) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1666546 + ... + 1666557.

It is an arithmetic number, because the mean of its divisors is an integer number (4999656).

Almost surely, 2^19998618 is an apocalyptic number.

19998618 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

19998618 is a wasteful number, since it uses less digits than its factorization.

19998618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3333108.

The product of its digits is 279936, while the sum is 51.

The square root of 19998618 is about 4471.9814400330. The cubic root of 19998618 is about 271.4355093069.

The spelling of 19998618 in words is "nineteen million, nine hundred ninety-eight thousand, six hundred eighteen".