It is a happy number.
It is a nialpdrome in base 10.
It is an unprimeable number.
Almost surely, 29999980 is an apocalyptic number.
It is an amenable number.
It is a practical number, because each smaller number is the sum of distinct divisors of 9999980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10924704).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
9999980 is a wasteful number, since it uses less digits than its factorization.
9999980 is an odious number, because the sum of its binary digits is odd.
The square root of 9999980 is about 3162.2744978891. The cubic root of 9999980 is about 215.4433253741.
The spelling of 9999980 in words is "nine million, nine hundred ninety-nine thousand, nine hundred eighty".