It is a happy number.
999989 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
It is a de Polignac number, because none of the positive numbers 2k-999989 is a prime.
It is a Duffinian number.
It is a Curzon number.
It is a self number, because there is not a number n which added to its sum of digits gives 999989.
It is a congruent number.
2999989 is an apocalyptic number.
It is an amenable number.
999989 is a wasteful number, since it uses less digits than its factorization.
999989 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 52650.
The square root of 999989 is about 999.9944999849. The cubic root of 999989 is about 99.9996333320. Note that the first 3 decimals are identical.
The spelling of 999989 in words is "nine hundred ninety-nine thousand, nine hundred eighty-nine".