18378993 has 8 divisors (see below), whose sum is σ = 24573568. Its totient is φ = 12218544.

The previous prime is 18378979. The next prime is 18379003. The reversal of 18378993 is 39987381.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 18378993 - 2⁴ = 18378977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18378923) 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 7 ways as a sum of consecutive naturals, for example, 7246 + ... + 9447.

It is an arithmetic number, because the mean of its divisors is an integer number (3071696).

Almost surely, 2^18378993 is an apocalyptic number.

It is an amenable number.

18378993 is a deficient number, since it is larger than the sum of its proper divisors (6194575).

18378993 is a wasteful number, since it uses less digits than its factorization.

18378993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17063.

The product of its digits is 326592, while the sum is 48.

The square root of 18378993 is about 4287.0727775488. The cubic root of 18378993 is about 263.9007173736.

The spelling of 18378993 in words is "eighteen million, three hundred seventy-eight thousand, nine hundred ninety-three".