9978 is nontrivially palindromic in base 5.
It is a sphenic number, since it is the product of 3 distinct primes.
9978 is an admirable number.
It is a nialpdrome in base 11.
29978 is an apocalyptic number.
9978 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
9978 is a wasteful number, since it uses less digits than its factorization.
9978 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 1668.
The square root of 9978 is about 99.8899394334. The cubic root of 9978 is about 21.5285361123.
Adding to 9978 its sum of digits (33), we get a triangular number (10011 = T141).
The spelling of 9978 in words is "nine thousand, nine hundred seventy-eight".