18369381 has 4 divisors (see below), whose sum is σ = 24492512. Its totient is φ = 12246252.

The previous prime is 18369359. The next prime is 18369389. The reversal of 18369381 is 18396381.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 18396381 = 3 ⋅6132127.

It is not a de Polignac number, because 18369381 - 2⁵ = 18369349 is a prime.

It is a super-2 number, since 2×18369381² = 674868316646322, 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 (18369389) 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 3 ways as a sum of consecutive naturals, for example, 3061561 + ... + 3061566.

It is an arithmetic number, because the mean of its divisors is an integer number (6123128).

Almost surely, 2^18369381 is an apocalyptic number.

It is an amenable number.

18369381 is a deficient number, since it is larger than the sum of its proper divisors (6123131).

18369381 is an equidigital number, since it uses as much as digits as its factorization.

18369381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6123130.

The product of its digits is 31104, while the sum is 39.

The square root of 18369381 is about 4285.9515862875. The cubic root of 18369381 is about 263.8547036805.

Subtracting 18369381 from its reverse (18396381), we obtain a cube (27000 = 30³).

The spelling of 18369381 in words is "eighteen million, three hundred sixty-nine thousand, three hundred eighty-one".