999996 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 congruent number.
It is an unprimeable number.
999996 is an untouchable number, because it is not equal to the sum of proper divisors of any number.
2999996 is an apocalyptic number.
It is an amenable number.
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
999996 is a wasteful number, since it uses less digits than its factorization.
999996 is an evil number, because the sum of its binary digits is even.
The square root of 999996 is about 999.9979999980. The cubic root of 999996 is about 99.9998666665. Note that the first 3 decimals are identical.
The spelling of 999996 in words is "nine hundred ninety-nine thousand, nine hundred ninety-six".