12221212221 has 18 divisors (see below), whose sum is σ = 18142879482. Its totient is φ = 7927264800.

The previous prime is 12221212187. The next prime is 12221212247.

It is a happy number.

12221212221 is a `hidden beast` number, since 12 + 221 + 212 + 221 = 666.

12221212221 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in 3 ways, for example, as 7918508196 + 4302704025 = 88986^2 + 65595^2 .

It is not a de Polignac number, because 12221212221 - 2¹¹ = 12221210173 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 12221212194 and 12221212203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12221219221) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 483630 + ... + 508271.

It is an arithmetic number, because the mean of its divisors is an integer number (1007937749).

Almost surely, 2^12221212221 is an apocalyptic number.

It is an amenable number.

12221212221 is a deficient number, since it is larger than the sum of its proper divisors (5921667261).

12221212221 is an equidigital number, since it uses as much as digits as its factorization.

12221212221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 991981 (or 991941 counting only the distinct ones).

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

The spelling of 12221212221 in words is "twelve billion, two hundred twenty-one million, two hundred twelve thousand, two hundred twenty-one".