2211121211221 has 4 divisors (see below), whose sum is σ = 2381207458252. Its totient is φ = 2041034964192.

The previous prime is 2211121211213. The next prime is 2211121211263. The reversal of 2211121211221 is 1221121211122.

It is a happy number.

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 1198501647121 + 1012619564100 = 1094761^2 + 1006290^2 .

It is a cyclic number.

It is not a de Polignac number, because 2211121211221 - 2³ = 2211121211213 is a prime.

It is a super-2 number, since 2×2211121211221² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2211121212221) 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, 85043123496 + ... + 85043123521.

It is an arithmetic number, because the mean of its divisors is an integer number (595301864563).

Almost surely, 2^{2211121211221} is an apocalyptic number.

It is an amenable number.

2211121211221 is a deficient number, since it is larger than the sum of its proper divisors (170086247031).

2211121211221 is a wasteful number, since it uses less digits than its factorization.

2211121211221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 170086247030.

The product of its digits is 64, while the sum is 19.

Adding to 2211121211221 its reverse (1221121211122), we get a palindrome (3432242422343).

Subtracting from 2211121211221 its reverse (1221121211122), we obtain a palindrome (990000000099).

The spelling of 2211121211221 in words is "two trillion, two hundred eleven billion, one hundred twenty-one million, two hundred eleven thousand, two hundred twenty-one".