999099900 divided by its reverse (9990999) gives a square (100 = 102).
It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.
It is a congruent number.
Almost surely, 2999099900 is an apocalyptic number.
999099900 is a gapful number since it is divisible by the number (90) formed by its first and last digit.
It is an amenable number.
It is a practical number, because each smaller number is the sum of distinct divisors of 999099900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1684163040).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
999099900 is a wasteful number, since it uses less digits than its factorization.
999099900 is an evil number, because the sum of its binary digits is even.
The square root of 999099900 is about 31608.5415671144. The cubic root of 999099900 is about 999.6998766016.
The spelling of 999099900 in words is "nine hundred ninety-nine million, ninety-nine thousand, nine hundred".