1211323011221 has 4 divisors (see below), whose sum is σ = 1211326508844. Its totient is φ = 1211319513600.

The previous prime is 1211323011193. The next prime is 1211323011251. The reversal of 1211323011221 is 1221103231121.

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 349563555121 + 861759456100 = 591239^2 + 928310^2 .

It is a cyclic number.

It is not a de Polignac number, because 1211323011221 - 2¹⁰ = 1211323010197 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1211323011193 and 1211323011202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211323011251) 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, 1164170 + ... + 1943691.

It is an arithmetic number, because the mean of its divisors is an integer number (302831627211).

Almost surely, 2^{1211323011221} is an apocalyptic number.

It is an amenable number.

1211323011221 is a deficient number, since it is larger than the sum of its proper divisors (3497623).

1211323011221 is an equidigital number, since it uses as much as digits as its factorization.

1211323011221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3497622.

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

Adding to 1211323011221 its reverse (1221103231121), we get a palindrome (2432426242342).

The spelling of 1211323011221 in words is "one trillion, two hundred eleven billion, three hundred twenty-three million, eleven thousand, two hundred twenty-one".