17998 has 4 divisors (see below), whose sum is σ = 27000. Its totient is φ = 8998.

The previous prime is 17989. The next prime is 18013. The reversal of 17998 is 89971.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 89971 = 7 ⋅12853.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4498 + ... + 4501.

It is an arithmetic number, because the mean of its divisors is an integer number (6750).

2¹⁷⁹⁹⁸ is an apocalyptic number.

17998 is a deficient number, since it is larger than the sum of its proper divisors (9002).

17998 is an equidigital number, since it uses as much as digits as its factorization.

17998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9001.

The product of its digits is 4536, while the sum is 34.

The square root of 17998 is about 134.1566248830. The cubic root of 17998 is about 26.2064432612.

The spelling of 17998 in words is "seventeen thousand, nine hundred ninety-eight".