21111111111112 is nontrivially palindromic in base 10.
Almost surely, 221111111111112 is an apocalyptic number.
21111111111112 is a gapful number since it is divisible by the number (22) formed by its first and last digit.
It is an amenable number.
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
21111111111112 is a wasteful number, since it uses less digits than its factorization.
21111111111112 is an odious number, because the sum of its binary digits is odd.
The spelling of 21111111111112 in words is "twenty-one trillion, one hundred eleven billion, one hundred eleven million, one hundred eleven thousand, one hundred twelve".