212021121221 has 32 divisors (see below), whose sum is σ = 263984313600.
Its totient is φ = 165803235840.
The previous prime is 212021121199. The next prime is 212021121227. The reversal of 212021121221 is 122121120212.
It is a cyclic number.
It is not a de Polignac number, because 212021121221 - 230 = 210947379397 is a prime.
It is a self number, because there is not a number n which added to its sum of digits gives 212021121221.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (212021121227) by changing a digit.
It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 39933515 + ... + 39938823.
It is an arithmetic number, because the mean of its divisors is an integer number (8249509800).
Almost surely, 2212021121221 is an apocalyptic number.
It is an amenable number.
212021121221 is a deficient number, since it is larger than the sum of its proper divisors (51963192379).
212021121221 is a wasteful number, since it uses less digits than its factorization.
212021121221 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 10349.
The product of its (nonzero) digits is 64, while the sum is 17.
Adding to 212021121221 its reverse (122121120212), we get a palindrome (334142241433).
The spelling of 212021121221 in words is "two hundred twelve billion, twenty-one million, one hundred twenty-one thousand, two hundred twenty-one".