81453968561 has 16 divisors (see below), whose sum is σ = 95163926400. Its totient is φ = 69689889360.

The previous prime is 81453968527. The next prime is 81453968579. The reversal of 81453968561 is 16586935418.

It is not a de Polignac number, because 81453968561 - 2³⁰ = 80380226737 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 81453968497 and 81453968506.

It is not an unprimeable number, because it can be changed into a prime (81453967561) 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 15 ways as a sum of consecutive naturals, for example, 29450 + ... + 404691.

It is an arithmetic number, because the mean of its divisors is an integer number (5947745400).

Almost surely, 2^81453968561 is an apocalyptic number.

It is an amenable number.

81453968561 is a deficient number, since it is larger than the sum of its proper divisors (13709957839).

81453968561 is an equidigital number, since it uses as much as digits as its factorization.

81453968561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 434709 (or 434695 counting only the distinct ones).

The product of its digits is 6220800, while the sum is 56.

The spelling of 81453968561 in words is "eighty-one billion, four hundred fifty-three million, nine hundred sixty-eight thousand, five hundred sixty-one".