18987984 has 30 divisors (see below), whose sum is σ = 53140386. Its totient is φ = 6329280.

The previous prime is 18987977. The next prime is 18988003. The reversal of 18987984 is 48978981.

It can be written as a sum of positive squares in only one way, i.e., 11370384 + 7617600 = 3372^2 + 2760^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 18987984.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 65787 + ... + 66074.

Almost surely, 2^18987984 is an apocalyptic number.

It is an amenable number.

18987984 is an abundant number, since it is smaller than the sum of its proper divisors (34152402).

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

18987984 is a wasteful number, since it uses less digits than its factorization.

18987984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131875 (or 131866 counting only the distinct ones).

The product of its digits is 1161216, while the sum is 54.

The square root of 18987984 is about 4357.5203958215. The cubic root of 18987984 is about 266.7839012304.

The spelling of 18987984 in words is "eighteen million, nine hundred eighty-seven thousand, nine hundred eighty-four".