998 can be written using four 4's:
See also 113
998 has 4
divisors (see below), whose sum is σ = 1500
Its totient is φ = 498
The previous prime is 997. The next prime is 1009. The reversal of 998 is 899.
It is a happy number.
998 is nontrivially palindromic in base 11.
It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 899 = 29 ⋅31.
It is a magnanimous number.
998 is an undulating number in base 11.
It is a Curzon number.
It is a plaindrome in base 15.
It is a nialpdrome in base 10.
It is a zygodrome in base 3.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (991) by changing a digit.
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, 248 + ... + 251.
It is an arithmetic number, because the mean of its divisors is an integer number (375).
998 is a deficient number, since it is larger than the sum of its proper divisors (502).
998 is a wasteful number, since it uses less digits than its factorization.
998 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 501.
The product of its digits is 648, while the sum is 26.
The square root of 998 is about 31.5911379979.
The cubic root of 998 is about 9.9933288839.
Adding to 998 its sum of digits (26), we get a 10-th power (1024 = 210).
Subtracting from 998 its reverse (899), we obtain a palindrome (99).
The spelling of 998 in words is "nine hundred ninety-eight", and thus it is an aban number and an oban number.