1211231310221 has 4 divisors (see below), whose sum is σ = 1211475958944. Its totient is φ = 1210986661500.

The previous prime is 1211231310203. The next prime is 1211231310293. The reversal of 1211231310221 is 1220131321121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1211231310221 - 2³⁰ = 1210157568397 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1211231310193 and 1211231310202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211231310521) 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, 122316935 + ... + 122326836.

It is an arithmetic number, because the mean of its divisors is an integer number (302868989736).

Almost surely, 2^{1211231310221} is an apocalyptic number.

It is an amenable number.

1211231310221 is a deficient number, since it is larger than the sum of its proper divisors (244648723).

1211231310221 is an equidigital number, since it uses as much as digits as its factorization.

1211231310221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 244648722.

The product of its (nonzero) digits is 144, while the sum is 20.

Adding to 1211231310221 its reverse (1220131321121), we get a palindrome (2431362631342).

The spelling of 1211231310221 in words is "one trillion, two hundred eleven billion, two hundred thirty-one million, three hundred ten thousand, two hundred twenty-one".