13221971881 has 2 divisors, whose sum is σ = 13221971882. Its totient is φ = 13221971880.

The previous prime is 13221971849. The next prime is 13221971909. The reversal of 13221971881 is 18817912231.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8900224281 + 4321747600 = 94341^2 + 65740^2 .

It is a cyclic number.

It is not a de Polignac number, because 13221971881 - 2⁵ = 13221971849 is a prime.

It is a super-2 number, since 2×13221971881² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (13221971801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6610985940 + 6610985941.

It is an arithmetic number, because the mean of its divisors is an integer number (6610985941).

Almost surely, 2^13221971881 is an apocalyptic number.

It is an amenable number.

13221971881 is a deficient number, since it is larger than the sum of its proper divisors (1).

13221971881 is an equidigital number, since it uses as much as digits as its factorization.

13221971881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 48384, while the sum is 43.

The spelling of 13221971881 in words is "thirteen billion, two hundred twenty-one million, nine hundred seventy-one thousand, eight hundred eighty-one".