18387381 has 8 divisors (see below), whose sum is σ = 24591904. Its totient is φ = 12220560.

The previous prime is 18387377. The next prime is 18387403. The reversal of 18387381 is 18378381.

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

It is not a de Polignac number, because 18387381 - 2² = 18387377 is a prime.

It is a super-2 number, since 2×18387381² = 676191560078322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18387301) 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, 8266 + ... + 10251.

It is an arithmetic number, because the mean of its divisors is an integer number (3073988).

Almost surely, 2^18387381 is an apocalyptic number.

It is an amenable number.

18387381 is a deficient number, since it is larger than the sum of its proper divisors (6204523).

18387381 is a wasteful number, since it uses less digits than its factorization.

18387381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18851.

The product of its digits is 32256, while the sum is 39.

The square root of 18387381 is about 4288.0509558540. The cubic root of 18387381 is about 263.9408585381.

The spelling of 18387381 in words is "eighteen million, three hundred eighty-seven thousand, three hundred eighty-one".