13221433516561 has 2 divisors, whose sum is σ = 13221433516562. Its totient is φ = 13221433516560.

The previous prime is 13221433516553. The next prime is 13221433516573. The reversal of 13221433516561 is 16561533412231.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11551290840961 + 1670142675600 = 3398719^2 + 1292340^2 .

It is a cyclic number.

It is not a de Polignac number, because 13221433516561 - 2³ = 13221433516553 is a prime.

It is a super-2 number, since 2×13221433516561² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (13221433516261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6610716758280 + 6610716758281.

It is an arithmetic number, because the mean of its divisors is an integer number (6610716758281).

Almost surely, 2^{13221433516561} is an apocalyptic number.

It is an amenable number.

13221433516561 is a deficient number, since it is larger than the sum of its proper divisors (1).

13221433516561 is an equidigital number, since it uses as much as digits as its factorization.

13221433516561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 388800, while the sum is 43.

Adding to 13221433516561 its reverse (16561533412231), we get a palindrome (29782966928792).

The spelling of 13221433516561 in words is "thirteen trillion, two hundred twenty-one billion, four hundred thirty-three million, five hundred sixteen thousand, five hundred sixty-one".