12122212221 has 84 divisors (see below), whose sum is σ = 21107211552. Its totient is φ = 6816184992.

The previous prime is 12122212213. The next prime is 12122212229. The reversal of 12122212221 is 12221222121.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (12122212213) and next prime (12122212229).

It is not a de Polignac number, because 12122212221 - 2³ = 12122212213 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 12122212194 and 12122212203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12122212229) by changing a digit.

It is a polite number, since it can be written in 83 ways as a sum of consecutive naturals, for example, 81357055 + ... + 81357203.

It is an arithmetic number, because the mean of its divisors is an integer number (251276328).

Almost surely, 2^12122212221 is an apocalyptic number.

It is an amenable number.

12122212221 is a deficient number, since it is larger than the sum of its proper divisors (8984999331).

12122212221 is an frugal number, since it uses more digits than its factorization.

12122212221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 430 (or 266 counting only the distinct ones).

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

Adding to 12122212221 its reverse (12221222121), we get a palindrome (24343434342).

The spelling of 12122212221 in words is "twelve billion, one hundred twenty-two million, two hundred twelve thousand, two hundred twenty-one".