81608417641 has 2 divisors, whose sum is σ = 81608417642. Its totient is φ = 81608417640.

The previous prime is 81608417609. The next prime is 81608417677. The reversal of 81608417641 is 14671480618.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 78781262400 + 2827155241 = 280680^2 + 53171^2 .

It is a cyclic number.

It is not a de Polignac number, because 81608417641 - 2⁵ = 81608417609 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81608417591 and 81608417600.

It is not a weakly prime, because it can be changed into another prime (81608411641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40804208820 + 40804208821.

It is an arithmetic number, because the mean of its divisors is an integer number (40804208821).

Almost surely, 2^81608417641 is an apocalyptic number.

It is an amenable number.

81608417641 is a deficient number, since it is larger than the sum of its proper divisors (1).

81608417641 is an equidigital number, since it uses as much as digits as its factorization.

81608417641 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 258048, while the sum is 46.

The spelling of 81608417641 in words is "eighty-one billion, six hundred eight million, four hundred seventeen thousand, six hundred forty-one".