It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 999816.
It is an unprimeable number.
2999816 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.
999816 is a wasteful number, since it uses less digits than its factorization.
999816 is an evil number, because the sum of its binary digits is even.
The square root of 999816 is about 999.9079957676. The cubic root of 999816 is about 99.9938662905.
The spelling of 999816 in words is "nine hundred ninety-nine thousand, eight hundred sixteen".