311201221381 has 2 divisors, whose sum is σ = 311201221382. Its totient is φ = 311201221380.

The previous prime is 311201221379. The next prime is 311201221423. The reversal of 311201221381 is 183122102113.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 290294664100 + 20906557281 = 538790^2 + 144591^2 .

It is a cyclic number.

It is not a de Polignac number, because 311201221381 - 2¹ = 311201221379 is a prime.

It is a super-2 number, since 2×311201221381² (a number of 24 digits) contains 22 as substring.

Together with 311201221379, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (311201224381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 155600610690 + 155600610691.

It is an arithmetic number, because the mean of its divisors is an integer number (155600610691).

Almost surely, 2^311201221381 is an apocalyptic number.

It is an amenable number.

311201221381 is a deficient number, since it is larger than the sum of its proper divisors (1).

311201221381 is an equidigital number, since it uses as much as digits as its factorization.

311201221381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 25.

Adding to 311201221381 its reverse (183122102113), we get a palindrome (494323323494).

The spelling of 311201221381 in words is "three hundred eleven billion, two hundred one million, two hundred twenty-one thousand, three hundred eighty-one".