311131311221 has 4 divisors (see below), whose sum is σ = 311137543500. Its totient is φ = 311125078944.

The previous prime is 311131311203. The next prime is 311131311311. The reversal of 311131311221 is 122113131113.

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 158054748721 + 153076562500 = 397561^2 + 391250^2 .

It is a cyclic number.

It is not a de Polignac number, because 311131311221 - 2¹⁸ = 311131049077 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 311131311193 and 311131311202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (311131311121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3040646 + ... + 3141303.

It is an arithmetic number, because the mean of its divisors is an integer number (77784385875).

Almost surely, 2^311131311221 is an apocalyptic number.

It is an amenable number.

311131311221 is a deficient number, since it is larger than the sum of its proper divisors (6232279).

311131311221 is an equidigital number, since it uses as much as digits as its factorization.

311131311221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6232278.

The product of its digits is 108, while the sum is 20.

Adding to 311131311221 its reverse (122113131113), we get a palindrome (433244442334).

The spelling of 311131311221 in words is "three hundred eleven billion, one hundred thirty-one million, three hundred eleven thousand, two hundred twenty-one".