18240689 has 2 divisors, whose sum is σ = 18240690. Its totient is φ = 18240688.

The previous prime is 18240659. The next prime is 18240707. The reversal of 18240689 is 98604281.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17305600 + 935089 = 4160^2 + 967^2 .

It is a cyclic number.

It is not a de Polignac number, because 18240689 - 2¹² = 18236593 is a prime.

It is not a weakly prime, because it can be changed into another prime (18240619) 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 as a sum of consecutive naturals, namely, 9120344 + 9120345.

It is an arithmetic number, because the mean of its divisors is an integer number (9120345).

Almost surely, 2^18240689 is an apocalyptic number.

It is an amenable number.

18240689 is a deficient number, since it is larger than the sum of its proper divisors (1).

18240689 is an equidigital number, since it uses as much as digits as its factorization.

18240689 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 27648, while the sum is 38.

The square root of 18240689 is about 4270.9119635038. The cubic root of 18240689 is about 263.2370890429.

The spelling of 18240689 in words is "eighteen million, two hundred forty thousand, six hundred eighty-nine".