18998320 has 40 divisors (see below), whose sum is σ = 48188880. Its totient is φ = 6908160.

The previous prime is 18998281. The next prime is 18998321. The reversal of 18998320 is 2389981.

It is a tau number, because it is divible by the number of its divisors (40).

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is not an unprimeable number, because it can be changed into a prime (18998321) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9915 + ... + 11674.

It is an arithmetic number, because the mean of its divisors is an integer number (1204722).

Almost surely, 2^18998320 is an apocalyptic number.

18998320 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18998320 is an abundant number, since it is smaller than the sum of its proper divisors (29190560).

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

18998320 is a wasteful number, since it uses less digits than its factorization.

18998320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21613 (or 21607 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 40.

The square root of 18998320 is about 4358.7062300641. The cubic root of 18998320 is about 266.8322998776.

The spelling of 18998320 in words is "eighteen million, nine hundred ninety-eight thousand, three hundred twenty".