18008505 has 24 divisors (see below), whose sum is σ = 31387200. Its totient is φ = 9551520.

The previous prime is 18008503. The next prime is 18008519. The reversal of 18008505 is 50580081.

It is not a de Polignac number, because 18008505 - 2¹ = 18008503 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18008503) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7950 + ... + 9960.

It is an arithmetic number, because the mean of its divisors is an integer number (1307800).

Almost surely, 2^18008505 is an apocalyptic number.

18008505 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

18008505 is a deficient number, since it is larger than the sum of its proper divisors (13378695).

18008505 is a wasteful number, since it uses less digits than its factorization.

18008505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2221 (or 2218 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 27.

The square root of 18008505 is about 4243.6428926101. The cubic root of 18008505 is about 262.1154095985.

Adding to 18008505 its reverse (50580081), we get a palindrome (68588586).

The spelling of 18008505 in words is "eighteen million, eight thousand, five hundred five".