999999999999 is nontrivially palindromic in base 10.
It is a trimorphic number since its cube, 999999999997000000000002999999999999, ends in 999999999999.
It is a nude number because it is divisible by every one of its digits.
999999999999 is a nontrivial repdigit in base 10.
It is a plaindrome in base 10.
It is a nialpdrome in base 10.
It is a zygodrome in base 10.
It is a self number, because there is not a number n which added to its sum of digits gives 999999999999.
It is a congruent number.
It is a Kaprekar number, because its square (999999999998000000000001) can be partitioned into two parts whose sum is 999999999999.
Almost surely, 2999999999999 is an apocalyptic number.
999999999999 is a gapful number since it is divisible by the number (99) formed by its first and last digit.
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
999999999999 is a wasteful number, since it uses less digits than its factorization.
999999999999 is an evil number, because the sum of its binary digits is even.
The spelling of 999999999999 in words is "nine hundred ninety-nine billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred ninety-nine".