18987320 has 48 divisors (see below), whose sum is σ = 46970280. Its totient is φ = 6902720.

The previous prime is 18987313. The next prime is 18987323. The reversal of 18987320 is 2378981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18987323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2879 + ... + 6801.

Almost surely, 2^18987320 is an apocalyptic number.

18987320 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 18987320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23485140).

18987320 is an abundant number, since it is smaller than the sum of its proper divisors (27982960).

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

18987320 is a wasteful number, since it uses less digits than its factorization.

18987320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3956 (or 3941 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 38.

The square root of 18987320 is about 4357.4442050358. Note that the first 3 decimals coincide. The cubic root of 18987320 is about 266.7807914291.

The spelling of 18987320 in words is "eighteen million, nine hundred eighty-seven thousand, three hundred twenty".