81648084689 has 2 divisors, whose sum is σ = 81648084690. Its totient is φ = 81648084688.

The previous prime is 81648084613. The next prime is 81648084691. The reversal of 81648084689 is 98648084618.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 81316225600 + 331859089 = 285160^2 + 18217^2 .

It is a cyclic number.

It is not a de Polignac number, because 81648084689 - 2¹² = 81648080593 is a prime.

Together with 81648084691, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (81648084589) 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, 40824042344 + 40824042345.

It is an arithmetic number, because the mean of its divisors is an integer number (40824042345).

Almost surely, 2^81648084689 is an apocalyptic number.

It is an amenable number.

81648084689 is a deficient number, since it is larger than the sum of its proper divisors (1).

81648084689 is an equidigital number, since it uses as much as digits as its factorization.

81648084689 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 21233664, while the sum is 62.

The spelling of 81648084689 in words is "eighty-one billion, six hundred forty-eight million, eighty-four thousand, six hundred eighty-nine".