311311220221 has 2 divisors, whose sum is σ = 311311220222. Its totient is φ = 311311220220.

The previous prime is 311311220153. The next prime is 311311220243. The reversal of 311311220221 is 122022113113.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 306485139321 + 4826080900 = 553611^2 + 69470^2 .

It is a cyclic number.

It is not a de Polignac number, because 311311220221 - 2¹⁹ = 311310695933 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (311311220261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 155655610110 + 155655610111.

It is an arithmetic number, because the mean of its divisors is an integer number (155655610111).

Almost surely, 2^311311220221 is an apocalyptic number.

It is an amenable number.

311311220221 is a deficient number, since it is larger than the sum of its proper divisors (1).

311311220221 is an equidigital number, since it uses as much as digits as its factorization.

311311220221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 19.

Adding to 311311220221 its reverse (122022113113), we get a palindrome (433333333334).

The spelling of 311311220221 in words is "three hundred eleven billion, three hundred eleven million, two hundred twenty thousand, two hundred twenty-one".