18381238 has 8 divisors (see below), whose sum is σ = 27660888. Its totient is φ = 9160944.

The previous prime is 18381229. The next prime is 18381239. The reversal of 18381238 is 83218381.

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

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18381239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14056 + ... + 15307.

It is an arithmetic number, because the mean of its divisors is an integer number (3457611).

Almost surely, 2^18381238 is an apocalyptic number.

18381238 is a deficient number, since it is larger than the sum of its proper divisors (9279650).

18381238 is a wasteful number, since it uses less digits than its factorization.

18381238 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29678.

The product of its digits is 9216, while the sum is 34.

The square root of 18381238 is about 4287.3346032238. The cubic root of 18381238 is about 263.9114621224.

The spelling of 18381238 in words is "eighteen million, three hundred eighty-one thousand, two hundred thirty-eight".