18440839 has 4 divisors (see below), whose sum is σ = 19076760. Its totient is φ = 17804920.

The previous prime is 18440833. The next prime is 18440861. The reversal of 18440839 is 93804481.

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

It is a cyclic number.

It is not a de Polignac number, because 18440839 - 2³ = 18440831 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18440798 and 18440807.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18440831) 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, 317917 + ... + 317974.

It is an arithmetic number, because the mean of its divisors is an integer number (4769190).

Almost surely, 2^18440839 is an apocalyptic number.

18440839 is a deficient number, since it is larger than the sum of its proper divisors (635921).

18440839 is an equidigital number, since it uses as much as digits as its factorization.

18440839 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 635920.

The product of its (nonzero) digits is 27648, while the sum is 37.

The square root of 18440839 is about 4294.2797999199. The cubic root of 18440839 is about 264.1963978961.

The spelling of 18440839 in words is "eighteen million, four hundred forty thousand, eight hundred thirty-nine".