18240505 has 4 divisors (see below), whose sum is σ = 21888612. Its totient is φ = 14592400.

The previous prime is 18240479. The next prime is 18240511. The reversal of 18240505 is 50504281.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14584761 + 3655744 = 3819^2 + 1912^2 .

It is not a de Polignac number, because 18240505 - 2⁷ = 18240377 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18240505.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1824046 + ... + 1824055.

It is an arithmetic number, because the mean of its divisors is an integer number (5472153).

Almost surely, 2^18240505 is an apocalyptic number.

It is an amenable number.

18240505 is a deficient number, since it is larger than the sum of its proper divisors (3648107).

18240505 is an equidigital number, since it uses as much as digits as its factorization.

18240505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3648106.

The product of its (nonzero) digits is 1600, while the sum is 25.

The square root of 18240505 is about 4270.8904223827. The cubic root of 18240505 is about 263.2362039194.

Adding to 18240505 its reverse (50504281), we get a palindrome (68744786).

The spelling of 18240505 in words is "eighteen million, two hundred forty thousand, five hundred five".