13111431381221 has 2 divisors, whose sum is σ = 13111431381222. Its totient is φ = 13111431381220.

The previous prime is 13111431381199. The next prime is 13111431381229. The reversal of 13111431381221 is 12218313411131.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8060687548225 + 5050743832996 = 2839135^2 + 2247386^2 .

It is an emirp because it is prime and its reverse (12218313411131) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 13111431381221 - 2²² = 13111427186917 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13111431381229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6555715690610 + 6555715690611.

It is an arithmetic number, because the mean of its divisors is an integer number (6555715690611).

Almost surely, 2^{13111431381221} is an apocalyptic number.

It is an amenable number.

13111431381221 is a deficient number, since it is larger than the sum of its proper divisors (1).

13111431381221 is an equidigital number, since it uses as much as digits as its factorization.

13111431381221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3456, while the sum is 32.

Adding to 13111431381221 its reverse (12218313411131), we get a palindrome (25329744792352).

The spelling of 13111431381221 in words is "thirteen trillion, one hundred eleven billion, four hundred thirty-one million, three hundred eighty-one thousand, two hundred twenty-one".