685739 has 2 divisors, whose sum is σ = 685740. Its totient is φ = 685738.

The previous prime is 685733. The next prime is 685747. The reversal of 685739 is 937586.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 685739 - 2⁴ = 685723 is a prime.

It is a super-2 number, since 2×685739² = 940475952242, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (685733) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342869 + 342870.

It is an arithmetic number, because the mean of its divisors is an integer number (342870).

2⁶⁸⁵⁷³⁹ is an apocalyptic number.

685739 is a deficient number, since it is larger than the sum of its proper divisors (1).

685739 is an equidigital number, since it uses as much as digits as its factorization.

685739 is an evil number, because the sum of its binary digits is even.

The product of its digits is 45360, while the sum is 38.

The square root of 685739 is about 828.0935937441. The cubic root of 685739 is about 88.1832870604.

The spelling of 685739 in words is "six hundred eighty-five thousand, seven hundred thirty-nine".