18008939 has 4 divisors (see below), whose sum is σ = 19394256. Its totient is φ = 16623624.

The previous prime is 18008917. The next prime is 18008989. The reversal of 18008939 is 93980081.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18008939 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18008989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 692639 + ... + 692664.

It is an arithmetic number, because the mean of its divisors is an integer number (4848564).

Almost surely, 2^18008939 is an apocalyptic number.

18008939 is a deficient number, since it is larger than the sum of its proper divisors (1385317).

18008939 is a wasteful number, since it uses less digits than its factorization.

18008939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1385316.

The product of its (nonzero) digits is 15552, while the sum is 38.

The square root of 18008939 is about 4243.6940276132. The cubic root of 18008939 is about 262.1175152179.

The spelling of 18008939 in words is "eighteen million, eight thousand, nine hundred thirty-nine".