1211213322221 has 18 divisors (see below), whose sum is σ = 1455879035790. Its totient is φ = 1004693039280.

The previous prime is 1211213322167. The next prime is 1211213322247. The reversal of 1211213322221 is 1222233121121.

It can be written as a sum of positive squares in only one way, i.e., 1107651002500 + 103562319721 = 1052450^2 + 321811^2 .

It is a de Polignac number, because none of the positive numbers 2^k-1211213322221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211213322251) 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, 12813806 + ... + 12907983.

It is an arithmetic number, because the mean of its divisors is an integer number (80882168655).

Almost surely, 2^{1211213322221} is an apocalyptic number.

It is an amenable number.

1211213322221 is a deficient number, since it is larger than the sum of its proper divisors (244665713569).

1211213322221 is an equidigital number, since it uses as much as digits as its factorization.

1211213322221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25721865 (or 25721827 counting only the distinct ones).

The product of its digits is 576, while the sum is 23.

Adding to 1211213322221 its reverse (1222233121121), we get a palindrome (2433446443342).

The spelling of 1211213322221 in words is "one trillion, two hundred eleven billion, two hundred thirteen million, three hundred twenty-two thousand, two hundred twenty-one".