18240215 has 16 divisors (see below), whose sum is σ = 25489728. Its totient is φ = 12270336.

The previous prime is 18240191. The next prime is 18240221. The reversal of 18240215 is 51204281.

It is a cyclic number.

It is not a de Polignac number, because 18240215 - 2⁶ = 18240151 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 in 15 ways as a sum of consecutive naturals, for example, 3062 + ... + 6771.

It is an arithmetic number, because the mean of its divisors is an integer number (1593108).

Almost surely, 2^18240215 is an apocalyptic number.

18240215 is a deficient number, since it is larger than the sum of its proper divisors (7249513).

18240215 is an equidigital number, since it uses as much as digits as its factorization.

18240215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9898.

The product of its (nonzero) digits is 640, while the sum is 23.

The square root of 18240215 is about 4270.8564714820. The cubic root of 18240215 is about 263.2348088757.

Adding to 18240215 its reverse (51204281), we get a palindrome (69444496).

The spelling of 18240215 in words is "eighteen million, two hundred forty thousand, two hundred fifteen".