212021122221 has 24 divisors (see below), whose sum is σ = 309042260280. Its totient is φ = 140060583936.

The previous prime is 212021122177. The next prime is 212021122259. The reversal of 212021122221 is 122221120212.

It is a happy number.

212021122221 is a `hidden beast` number, since 212 + 0 + 211 + 22 + 221 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 2816424900 + 209204697321 = 53070^2 + 457389^2 .

It is not a de Polignac number, because 212021122221 - 2⁹ = 212021121709 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 212021122194 and 212021122203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212021192221) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4276245 + ... + 4325541.

It is an arithmetic number, because the mean of its divisors is an integer number (12876760845).

Almost surely, 2^212021122221 is an apocalyptic number.

It is an amenable number.

212021122221 is a deficient number, since it is larger than the sum of its proper divisors (97021138059).

212021122221 is a wasteful number, since it uses less digits than its factorization.

212021122221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53645 (or 53642 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 212021122221 its reverse (122221120212), we get a palindrome (334242242433).

The spelling of 212021122221 in words is "two hundred twelve billion, twenty-one million, one hundred twenty-two thousand, two hundred twenty-one".