18687844 has 12 divisors (see below), whose sum is σ = 37375744. Its totient is φ = 8009064.

The previous prime is 18687821. The next prime is 18687859. The reversal of 18687844 is 44878681.

It is a happy number.

18687844 is an admirable number.

It is a junction number, because it is equal to n+sod(n) for n = 18687794 and 18687803.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 333684 + ... + 333739.

Almost surely, 2^18687844 is an apocalyptic number.

18687844 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

18687844 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

18687844 is a wasteful number, since it uses less digits than its factorization.

18687844 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 667434 (or 667432 counting only the distinct ones).

The product of its digits is 344064, while the sum is 46.

The square root of 18687844 is about 4322.9439043319. The cubic root of 18687844 is about 265.3707590674.

The spelling of 18687844 in words is "eighteen million, six hundred eighty-seven thousand, eight hundred forty-four".