9998 has 4 divisors (see below), whose sum is σ = 15000. Its totient is φ = 4998.

The previous prime is 9973. The next prime is 10007. The reversal of 9998 is 8999.

9998 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a Curzon number.

It is a nialpdrome in base 10.

It is a congruent number.

It is an unprimeable number.

9998 is an untouchable number, because it is not equal to the sum of proper divisors of any 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, 2498 + ... + 2501.

It is an arithmetic number, because the mean of its divisors is an integer number (3750).

9998 is a deficient number, since it is larger than the sum of its proper divisors (5002).

9998 is a wasteful number, since it uses less digits than its factorization.

9998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5001.

The product of its digits is 5832, while the sum is 35.

The square root of 9998 is about 99.9899994999. The cubic root of 9998 is about 21.5429105148.

Subtracting from 9998 its reverse (8999), we obtain a palindrome (999).

The spelling of 9998 in words is "nine thousand, nine hundred ninety-eight".