12212122221 has 24 divisors (see below), whose sum is σ = 19700218720. Its totient is φ = 7515150192.

The previous prime is 12212122213. The next prime is 12212122243. The reversal of 12212122221 is 12222121221.

It is a happy number.

It is not a de Polignac number, because 12212122221 - 2³ = 12212122213 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 12212122194 and 12212122203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12212122211) 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, 1929751 + ... + 1936068.

Almost surely, 2^12212122221 is an apocalyptic number.

It is an amenable number.

12212122221 is a deficient number, since it is larger than the sum of its proper divisors (7488096499).

12212122221 is an equidigital number, since it uses as much as digits as its factorization.

12212122221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3865847 (or 3865835 counting only the distinct ones).

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

Adding to 12212122221 its reverse (12222121221), we get a palindrome (24434243442).

The spelling of 12212122221 in words is "twelve billion, two hundred twelve million, one hundred twenty-two thousand, two hundred twenty-one".