13563320681 has 4 divisors (see below), whose sum is σ = 14361163092. Its totient is φ = 12765478272.

The previous prime is 13563320671. The next prime is 13563320723. The reversal of 13563320681 is 18602336531.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18602336531 = 1321 ⋅14082011.

It can be written as a sum of positive squares in 2 ways, for example, as 4325035225 + 9238285456 = 65765^2 + 96116^2 .

It is a cyclic number.

It is not a de Polignac number, because 13563320681 - 2¹⁰ = 13563319657 is a prime.

It is a super-2 number, since 2×13563320681² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (13563320611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 398921180 + ... + 398921213.

It is an arithmetic number, because the mean of its divisors is an integer number (3590290773).

Almost surely, 2^13563320681 is an apocalyptic number.

It is an amenable number.

13563320681 is a deficient number, since it is larger than the sum of its proper divisors (797842411).

13563320681 is an equidigital number, since it uses as much as digits as its factorization.

13563320681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 797842410.

The product of its (nonzero) digits is 77760, while the sum is 38.

The spelling of 13563320681 in words is "thirteen billion, five hundred sixty-three million, three hundred twenty thousand, six hundred eighty-one".