684739 has 6 divisors (see below), whose sum is σ = 752780. Its totient is φ = 622380.

The previous prime is 684731. The next prime is 684751. The reversal of 684739 is 937486.

684739 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 684739 - 2³ = 684731 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 684698 and 684707.

It is not an unprimeable number, because it can be changed into a prime (684731) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2709 + ... + 2950.

2⁶⁸⁴⁷³⁹ is an apocalyptic number.

684739 is a deficient number, since it is larger than the sum of its proper divisors (68041).

684739 is a wasteful number, since it uses less digits than its factorization.

684739 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5681 (or 5670 counting only the distinct ones).

The product of its digits is 36288, while the sum is 37.

The square root of 684739 is about 827.4895769736. The cubic root of 684739 is about 88.1404008763.

It can be divided in two parts, 6847 and 39, that added together give a palindrome (6886).

The spelling of 684739 in words is "six hundred eighty-four thousand, seven hundred thirty-nine".