18308505 has 16 divisors (see below), whose sum is σ = 29350080. Its totient is φ = 9745728.

The previous prime is 18308501. The next prime is 18308513. The reversal of 18308505 is 50580381.

It is a happy number.

It is not a de Polignac number, because 18308505 - 2² = 18308501 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18308501) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10806 + ... + 12384.

It is an arithmetic number, because the mean of its divisors is an integer number (1834380).

Almost surely, 2^18308505 is an apocalyptic number.

18308505 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

18308505 is a deficient number, since it is larger than the sum of its proper divisors (11041575).

18308505 is a wasteful number, since it uses less digits than its factorization.

18308505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2360.

The product of its (nonzero) digits is 4800, while the sum is 30.

The square root of 18308505 is about 4278.8438859112. The cubic root of 18308505 is about 263.5629102288.

Adding to 18308505 its reverse (50580381), we get a palindrome (68888886).

The spelling of 18308505 in words is "eighteen million, three hundred eight thousand, five hundred five".