999689666 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
It is a sphenic number, since it is the product of 3 distinct primes.
999689666 is a strobogrammatic number because it is the same when read upside-down.
It is an unprimeable number.
Almost surely, 2999689666 is an apocalyptic number.
999689666 is a wasteful number, since it uses less digits than its factorization.
999689666 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 345936.
The square root of 999689666 is about 31617.8694095602. The cubic root of 999689666 is about 999.8965446307.
The spelling of 999689666 in words is "nine hundred ninety-nine million, six hundred eighty-nine thousand, six hundred sixty-six".