12211121221 has 4 divisors (see below), whose sum is σ = 13150438252. Its totient is φ = 11271804192.

The previous prime is 12211121207. The next prime is 12211121231. The reversal of 12211121221 is 12212111221.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 818760996 + 11392360225 = 28614^2 + 106735^2 .

It is a cyclic number.

It is not a de Polignac number, because 12211121221 - 2⁹ = 12211120709 is a prime.

It is a super-2 number, since 2×12211121221² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 12211121195 and 12211121204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12211121231) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 469658496 + ... + 469658521.

It is an arithmetic number, because the mean of its divisors is an integer number (3287609563).

Almost surely, 2^12211121221 is an apocalyptic number.

It is an amenable number.

12211121221 is a deficient number, since it is larger than the sum of its proper divisors (939317031).

12211121221 is an equidigital number, since it uses as much as digits as its factorization.

12211121221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 939317030.

The product of its digits is 32, while the sum is 16.

Adding to 12211121221 its reverse (12212111221), we get a palindrome (24423232442).

The spelling of 12211121221 in words is "twelve billion, two hundred eleven million, one hundred twenty-one thousand, two hundred twenty-one".