18007438 has 4 divisors (see below), whose sum is σ = 27011160. Its totient is φ = 9003718.

The previous prime is 18007361. The next prime is 18007447. The reversal of 18007438 is 83470081.

It is a happy number.

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

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

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, 4501858 + ... + 4501861.

It is an arithmetic number, because the mean of its divisors is an integer number (6752790).

Almost surely, 2^18007438 is an apocalyptic number.

18007438 is a deficient number, since it is larger than the sum of its proper divisors (9003722).

18007438 is an equidigital number, since it uses as much as digits as its factorization.

18007438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9003721.

The product of its (nonzero) digits is 5376, while the sum is 31.

The square root of 18007438 is about 4243.5171732892. The cubic root of 18007438 is about 262.1102327359.

The spelling of 18007438 in words is "eighteen million, seven thousand, four hundred thirty-eight".