681897739 has 2 divisors, whose sum is σ = 681897740. Its totient is φ = 681897738.

The previous prime is 681897737. The next prime is 681897809. The reversal of 681897739 is 937798186.

681897739 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 is a cyclic number.

It is not a de Polignac number, because 681897739 - 2¹ = 681897737 is a prime.

Together with 681897737, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (681897737) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340948869 + 340948870.

It is an arithmetic number, because the mean of its divisors is an integer number (340948870).

Almost surely, 2^681897739 is an apocalyptic number.

681897739 is a deficient number, since it is larger than the sum of its proper divisors (1).

681897739 is an equidigital number, since it uses as much as digits as its factorization.

681897739 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4572288, while the sum is 58.

The square root of 681897739 is about 26113.1717529679. The cubic root of 681897739 is about 880.1832172748.

The spelling of 681897739 in words is "six hundred eighty-one million, eight hundred ninety-seven thousand, seven hundred thirty-nine".