18008 has 8 divisors (see below), whose sum is σ = 33780. Its totient is φ = 9000.

The previous prime is 17989. The next prime is 18013. The reversal of 18008 is 80081.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is an unprimeable number.

18008 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1118 + ... + 1133.

2¹⁸⁰⁰⁸ is an apocalyptic number.

It is an amenable number.

18008 is a deficient number, since it is larger than the sum of its proper divisors (15772).

18008 is a wasteful number, since it uses less digits than its factorization.

18008 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2257 (or 2253 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 17.

The square root of 18008 is about 134.1938895777. The cubic root of 18008 is about 26.2112959469.

Adding to 18008 its reverse (80081), we get a palindrome (98089).

It can be divided in two parts, 1800 and 8, that multiplied together give a square (14400 = 120²).

The spelling of 18008 in words is "eighteen thousand, eight".