18391039 has 4 divisors (see below), whose sum is σ = 18401256. Its totient is φ = 18380824.

The previous prime is 18391019. The next prime is 18391123. The reversal of 18391039 is 93019381.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 18391039 - 2⁹ = 18390527 is a prime.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a junction number, because it is equal to n+sod(n) for n = 18390995 and 18391013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18391019) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1609 + ... + 6274.

It is an arithmetic number, because the mean of its divisors is an integer number (4600314).

Almost surely, 2^18391039 is an apocalyptic number.

18391039 is a deficient number, since it is larger than the sum of its proper divisors (10217).

18391039 is an equidigital number, since it uses as much as digits as its factorization.

18391039 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10216.

The product of its (nonzero) digits is 5832, while the sum is 34.

The square root of 18391039 is about 4288.4774687528. The cubic root of 18391039 is about 263.9583602447.

The spelling of 18391039 in words is "eighteen million, three hundred ninety-one thousand, thirty-nine".