18239321 has 2 divisors, whose sum is σ = 18239322. Its totient is φ = 18239320.

The previous prime is 18239311. The next prime is 18239323. The reversal of 18239321 is 12393281.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12503296 + 5736025 = 3536^2 + 2395^2 .

It is an emirp because it is prime and its reverse (12393281) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18239321 - 2⁶ = 18239257 is a prime.

Together with 18239323, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18239323) 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 as a sum of consecutive naturals, namely, 9119660 + 9119661.

It is an arithmetic number, because the mean of its divisors is an integer number (9119661).

Almost surely, 2^18239321 is an apocalyptic number.

It is an amenable number.

18239321 is a deficient number, since it is larger than the sum of its proper divisors (1).

18239321 is an equidigital number, since it uses as much as digits as its factorization.

18239321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2592, while the sum is 29.

The square root of 18239321 is about 4270.7518073520. The cubic root of 18239321 is about 263.2305081997.

The spelling of 18239321 in words is "eighteen million, two hundred thirty-nine thousand, three hundred twenty-one".