Adding to 99999990000000 its reverse (9999999), we get a palindrome (99999999999999).
Subtracting from 99999990000000 its reverse (9999999), we obtain a square (99999980000001 = 99999992).
99999990000000 divided by its reverse (9999999) gives a 7-th power (10000000 = 107).
It is a nialpdrome in base 10.
It is a zygodrome in base 10.
It is a congruent number.
It is an unprimeable number.
Almost surely, 299999990000000 is an apocalyptic number.
99999990000000 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 99999990000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (180641139120000).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
99999990000000 is an frugal number, since it uses more digits than its factorization.
99999990000000 is an odious number, because the sum of its binary digits is odd.
The spelling of 99999990000000 in words is "ninety-nine trillion, nine hundred ninety-nine billion, nine hundred ninety million", and thus it is an aban number.