681739 has 8 divisors (see below), whose sum is σ = 732240. Its totient is φ = 632736.

The previous prime is 681731. The next prime is 681763. The reversal of 681739 is 937186.

681739 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 681739 - 2³ = 681731 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (681731) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 669 + ... + 1345.

It is an arithmetic number, because the mean of its divisors is an integer number (91530).

2⁶⁸¹⁷³⁹ is an apocalyptic number.

681739 is a deficient number, since it is larger than the sum of its proper divisors (50501).

681739 is a wasteful number, since it uses less digits than its factorization.

681739 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 749.

The product of its digits is 9072, while the sum is 34.

The square root of 681739 is about 825.6748754807. The cubic root of 681739 is about 88.0114912680.

The spelling of 681739 in words is "six hundred eighty-one thousand, seven hundred thirty-nine".