18998990 has 32 divisors (see below), whose sum is σ = 35380800. Its totient is φ = 7340800.

The previous prime is 18998983. The next prime is 18999007. The reversal of 18998990 is 9989981.

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 60935 + ... + 61245.

It is an arithmetic number, because the mean of its divisors is an integer number (1105650).

Almost surely, 2^18998990 is an apocalyptic number.

18998990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18998990 is a deficient number, since it is larger than the sum of its proper divisors (16381810).

18998990 is a wasteful number, since it uses less digits than its factorization.

18998990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 508.

The product of its (nonzero) digits is 419904, while the sum is 53.

The square root of 18998990 is about 4358.7830870554. The cubic root of 18998990 is about 266.8354365679.

Subtracting from 18998990 its reverse (9989981), we obtain a palindrome (9009009).

The spelling of 18998990 in words is "eighteen million, nine hundred ninety-eight thousand, nine hundred ninety".