681563427737 has 2 divisors, whose sum is σ = 681563427738. Its totient is φ = 681563427736.

The previous prime is 681563427731. The next prime is 681563427773. The reversal of 681563427737 is 737724365186.

Together with next prime (681563427773) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 414361276681 + 267202151056 = 643709^2 + 516916^2 .

It is a cyclic number.

It is not a de Polignac number, because 681563427737 - 2²⁰ = 681562379161 is a prime.

It is not a weakly prime, because it can be changed into another prime (681563427731) 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 as a sum of consecutive naturals, namely, 340781713868 + 340781713869.

It is an arithmetic number, because the mean of its divisors is an integer number (340781713869).

Almost surely, 2^681563427737 is an apocalyptic number.

It is an amenable number.

681563427737 is a deficient number, since it is larger than the sum of its proper divisors (1).

681563427737 is an equidigital number, since it uses as much as digits as its factorization.

681563427737 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 35562240, while the sum is 59.

The spelling of 681563427737 in words is "six hundred eighty-one billion, five hundred sixty-three million, four hundred twenty-seven thousand, seven hundred thirty-seven".