18131329 has 4 divisors (see below), whose sum is σ = 18149040. Its totient is φ = 18113620.

The previous prime is 18131303. The next prime is 18131359. The reversal of 18131329 is 92313181.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 18131329 - 2⁵ = 18131297 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18131297 and 18131306.

It is not an unprimeable number, because it can be changed into a prime (18131359) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7219 + ... + 9400.

It is an arithmetic number, because the mean of its divisors is an integer number (4537260).

Almost surely, 2^18131329 is an apocalyptic number.

It is an amenable number.

18131329 is a deficient number, since it is larger than the sum of its proper divisors (17711).

18131329 is a wasteful number, since it uses less digits than its factorization.

18131329 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17710.

The product of its digits is 1296, while the sum is 28.

The square root of 18131329 is about 4258.0898299590. The cubic root of 18131329 is about 262.7099647403.

The spelling of 18131329 in words is "eighteen million, one hundred thirty-one thousand, three hundred twenty-nine".