685889 has 4 divisors (see below), whose sum is σ = 702660. Its totient is φ = 669120.

The previous prime is 685859. The next prime is 685907. The reversal of 685889 is 988586.

685889 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 207025 + 478864 = 455^2 + 692^2 .

It is a de Polignac number, because none of the positive numbers 2^k-685889 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a nialpdrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (685819) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8324 + ... + 8405.

It is an arithmetic number, because the mean of its divisors is an integer number (175665).

2⁶⁸⁵⁸⁸⁹ is an apocalyptic number.

It is an amenable number.

685889 is a deficient number, since it is larger than the sum of its proper divisors (16771).

685889 is a wasteful number, since it uses less digits than its factorization.

685889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16770.

The product of its digits is 138240, while the sum is 44.

The square root of 685889 is about 828.1841582643. The cubic root of 685889 is about 88.1897163913.

The spelling of 685889 in words is "six hundred eighty-five thousand, eight hundred eighty-nine".