212111122221 has 48 divisors (see below), whose sum is σ = 318809914800. Its totient is φ = 135781401600.

The previous prime is 212111122213. The next prime is 212111122303. The reversal of 212111122221 is 122221111212.

212111122221 is a `hidden beast` number, since 212 + 111 + 122 + 221 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 4571652996 + 207539469225 = 67614^2 + 455565^2 .

It is not a de Polignac number, because 212111122221 - 2³ = 212111122213 is a prime.

It is a super-2 number, since 2×212111122221² (a number of 23 digits) contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 212111122194 and 212111122203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (212111122621) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 10517055 + ... + 10537203.

It is an arithmetic number, because the mean of its divisors is an integer number (6641873225).

Almost surely, 2^212111122221 is an apocalyptic number.

It is an amenable number.

212111122221 is a deficient number, since it is larger than the sum of its proper divisors (106698792579).

212111122221 is a wasteful number, since it uses less digits than its factorization.

212111122221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20606 (or 20603 counting only the distinct ones).

The product of its digits is 64, while the sum is 18.

Adding to 212111122221 its reverse (122221111212), we get a palindrome (334332233433).

The spelling of 212111122221 in words is "two hundred twelve billion, one hundred eleven million, one hundred twenty-two thousand, two hundred twenty-one".