18240239 has 2 divisors, whose sum is σ = 18240240. Its totient is φ = 18240238.

The previous prime is 18240227. The next prime is 18240251. The reversal of 18240239 is 93204281.

It is a balanced prime because it is at equal distance from previous prime (18240227) and next prime (18240251).

It is an emirp because it is prime and its reverse (93204281) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18240239 - 2⁸ = 18239983 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18240139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9120119 + 9120120.

It is an arithmetic number, because the mean of its divisors is an integer number (9120120).

Almost surely, 2^18240239 is an apocalyptic number.

18240239 is a deficient number, since it is larger than the sum of its proper divisors (1).

18240239 is an equidigital number, since it uses as much as digits as its factorization.

18240239 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 18240239 is about 4270.8592812220. The cubic root of 18240239 is about 263.2349243282.

The spelling of 18240239 in words is "eighteen million, two hundred forty thousand, two hundred thirty-nine".