18172439 has 16 divisors (see below), whose sum is σ = 19994688. Its totient is φ = 16445952.

The previous prime is 18172423. The next prime is 18172459. The reversal of 18172439 is 93427181.

It is a cyclic number.

It is not a de Polignac number, because 18172439 - 2⁴ = 18172423 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18172399 and 18172408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18172459) 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 15 ways as a sum of consecutive naturals, for example, 104957 + ... + 105129.

It is an arithmetic number, because the mean of its divisors is an integer number (1249668).

Almost surely, 2^18172439 is an apocalyptic number.

18172439 is a deficient number, since it is larger than the sum of its proper divisors (1822249).

18172439 is a wasteful number, since it uses less digits than its factorization.

With its successor (18172440) it forms a Ruth-Aaron pair, since the sum of their prime factors is the same (394).

18172439 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 394.

The product of its digits is 12096, while the sum is 35.

The square root of 18172439 is about 4262.9143786851. The cubic root of 18172439 is about 262.9083663479.

The spelling of 18172439 in words is "eighteen million, one hundred seventy-two thousand, four hundred thirty-nine".