9999966 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
It is a nialpdrome in base 10.
It is a zygodrome in base 10.
It is a congruent number.
It is an unprimeable number.
Almost surely, 29999966 is an apocalyptic number.
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
9999966 is a wasteful number, since it uses less digits than its factorization.
9999966 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 87743.
The square root of 9999966 is about 3162.2722842918. The cubic root of 9999966 is about 215.4432248336.
The spelling of 9999966 in words is "nine million, nine hundred ninety-nine thousand, nine hundred sixty-six".