Adding to 12121020 its reverse (2012121), we get a palindrome (14133141).
It is a tau number, because it is divible by the number of its divisors (36).
It is a congruent number.
It is an unprimeable number.
Almost surely, 212121020 is an apocalyptic number.
12121020 is a gapful number since it is divisible by the number (10) 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.
12121020 is a wasteful number, since it uses less digits than its factorization.
12121020 is an odious number, because the sum of its binary digits is odd.
The square root of 12121020 is about 3481.5255276962. The cubic root of 12121020 is about 229.7099052141.
The spelling of 12121020 in words is "twelve million, one hundred twenty-one thousand, twenty".