1211311101221 has 16 divisors (see below), whose sum is σ = 1312343852400. Its totient is φ = 1118017353024.

The previous prime is 1211311101157. The next prime is 1211311101239. The reversal of 1211311101221 is 1221011131121.

It can be written as a sum of positive squares in 8 ways, for example, as 1178279856196 + 33031245025 = 1085486^2 + 181745^2 .

It is not a de Polignac number, because 1211311101221 - 2⁶ = 1211311101157 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1211311101221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211311101271) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26950115 + ... + 26995023.

It is an arithmetic number, because the mean of its divisors is an integer number (82021490775).

Almost surely, 2^{1211311101221} is an apocalyptic number.

It is an amenable number.

1211311101221 is a deficient number, since it is larger than the sum of its proper divisors (101032751179).

1211311101221 is an equidigital number, since it uses as much as digits as its factorization.

1211311101221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57225 (or 57199 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 17.

Adding to 1211311101221 its reverse (1221011131121), we get a palindrome (2432322232342).

The spelling of 1211311101221 in words is "one trillion, two hundred eleven billion, three hundred eleven million, one hundred one thousand, two hundred twenty-one".