18987244 has 12 divisors (see below), whose sum is σ = 33297264. Its totient is φ = 9473744.

The previous prime is 18987239. The next prime is 18987247. The reversal of 18987244 is 44278981.

It is a self number, because there is not a number n which added to its sum of digits gives 18987244.

It is not an unprimeable number, because it can be changed into a prime (18987247) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2707 + ... + 6730.

It is an arithmetic number, because the mean of its divisors is an integer number (2774772).

Almost surely, 2^18987244 is an apocalyptic number.

It is an amenable number.

18987244 is a deficient number, since it is larger than the sum of its proper divisors (14310020).

18987244 is a wasteful number, since it uses less digits than its factorization.

18987244 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9944 (or 9942 counting only the distinct ones).

The product of its digits is 129024, while the sum is 43.

The square root of 18987244 is about 4357.4354843187. The cubic root of 18987244 is about 266.7804354833.

The spelling of 18987244 in words is "eighteen million, nine hundred eighty-seven thousand, two hundred forty-four".