18990000 has 150 divisors (see below), whose sum is σ = 66725516. Its totient is φ = 5040000.

The previous prime is 18989959. The next prime is 18990017. The reversal of 18990000 is 9981.

It is a tau number, because it is divible by the number of its divisors (150).

It is an unprimeable number.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 89895 + ... + 90105.

Almost surely, 2^18990000 is an apocalyptic number.

18990000 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18990000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33362758).

18990000 is an abundant number, since it is smaller than the sum of its proper divisors (47735516).

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

18990000 is a wasteful number, since it uses less digits than its factorization.

18990000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 245 (or 221 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 27.

The square root of 18990000 is about 4357.7517139002. The cubic root of 18990000 is about 266.7933425928.

Adding to 18990000 its reverse (9981), we get a palindrome (18999981).

The spelling of 18990000 in words is "eighteen million, nine hundred ninety thousand".