21022012 is nontrivially palindromic in base 10.
It is a self number, because there is not a number n which added to its sum of digits gives 21022012.
It is a congruent number.
It is an unprimeable number.
Almost surely, 221022012 is an apocalyptic number.
21022012 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.
21022012 is a wasteful number, since it uses less digits than its factorization.
21022012 is an evil number, because the sum of its binary digits is even.
The square root of 21022012 is about 4584.9767720240. The cubic root of 21022012 is about 275.9887799122.
The spelling of 21022012 in words is "twenty-one million, twenty-two thousand, twelve".