18091438 has 4 divisors (see below), whose sum is σ = 27137160. Its totient is φ = 9045718.

The previous prime is 18091429. The next prime is 18091457. The reversal of 18091438 is 83419081.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 4522858 + ... + 4522861.

It is an arithmetic number, because the mean of its divisors is an integer number (6784290).

Almost surely, 2^18091438 is an apocalyptic number.

18091438 is a deficient number, since it is larger than the sum of its proper divisors (9045722).

18091438 is an equidigital number, since it uses as much as digits as its factorization.

18091438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9045721.

The product of its (nonzero) digits is 6912, while the sum is 34.

The square root of 18091438 is about 4253.4031081006. The cubic root of 18091438 is about 262.5171592713.

The spelling of 18091438 in words is "eighteen million, ninety-one thousand, four hundred thirty-eight".