681764457193 has 2 divisors, whose sum is σ = 681764457194. Its totient is φ = 681764457192.

The previous prime is 681764457191. The next prime is 681764457299. The reversal of 681764457193 is 391754467186.

It is a happy number.

681764457193 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 680695951849 + 1068505344 = 825043^2 + 32688^2 .

It is a cyclic number.

It is not a de Polignac number, because 681764457193 - 2¹ = 681764457191 is a prime.

Together with 681764457191, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (681764457191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340882228596 + 340882228597.

It is an arithmetic number, because the mean of its divisors is an integer number (340882228597).

Almost surely, 2^681764457193 is an apocalyptic number.

It is an amenable number.

681764457193 is a deficient number, since it is larger than the sum of its proper divisors (1).

681764457193 is an equidigital number, since it uses as much as digits as its factorization.

681764457193 is an evil number, because the sum of its binary digits is even.

The product of its digits is 30481920, while the sum is 61.

The spelling of 681764457193 in words is "six hundred eighty-one billion, seven hundred sixty-four million, four hundred fifty-seven thousand, one hundred ninety-three".