18331289 has 2 divisors, whose sum is σ = 18331290. Its totient is φ = 18331288.

The previous prime is 18331279. The next prime is 18331301. The reversal of 18331289 is 98213381.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17347225 + 984064 = 4165^2 + 992^2 .

It is a cyclic number.

It is not a de Polignac number, because 18331289 - 2¹² = 18327193 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (18331259) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9165644 + 9165645.

It is an arithmetic number, because the mean of its divisors is an integer number (9165645).

Almost surely, 2^18331289 is an apocalyptic number.

It is an amenable number.

18331289 is a deficient number, since it is larger than the sum of its proper divisors (1).

18331289 is an equidigital number, since it uses as much as digits as its factorization.

18331289 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10368, while the sum is 35.

The square root of 18331289 is about 4281.5054595317. The cubic root of 18331289 is about 263.6721951046.

The spelling of 18331289 in words is "eighteen million, three hundred thirty-one thousand, two hundred eighty-nine".