It is a plaindrome in base 13 and base 16.
It is a congruent number.
It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 9918.
It is an unprimeable number.
29918 is an apocalyptic number.
It is a practical number, because each smaller number is the sum of distinct divisors of 9918, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11700).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
9918 is a wasteful number, since it uses less digits than its factorization.
9918 is an odious number, because the sum of its binary digits is odd.
The square root of 9918 is about 99.5891560362. The cubic root of 9918 is about 21.4852973213.
The spelling of 9918 in words is "nine thousand, nine hundred eighteen".