13111431321221 has 2 divisors, whose sum is σ = 13111431321222. Its totient is φ = 13111431321220.

The previous prime is 13111431321199. The next prime is 13111431321239. The reversal of 13111431321221 is 12212313411131.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11740998192196 + 1370433129025 = 3426514^2 + 1170655^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-13111431321221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13111431381221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6555715660610 + 6555715660611.

It is an arithmetic number, because the mean of its divisors is an integer number (6555715660611).

Almost surely, 2^{13111431321221} is an apocalyptic number.

It is an amenable number.

13111431321221 is a deficient number, since it is larger than the sum of its proper divisors (1).

13111431321221 is an equidigital number, since it uses as much as digits as its factorization.

13111431321221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 864, while the sum is 26.

Adding to 13111431321221 its reverse (12212313411131), we get a palindrome (25323744732352).

The spelling of 13111431321221 in words is "thirteen trillion, one hundred eleven billion, four hundred thirty-one million, three hundred twenty-one thousand, two hundred twenty-one".