685720 has 64 divisors (see below), whose sum is σ = 1843200. Its totient is φ = 224640.

The previous prime is 685717. The next prime is 685723. The reversal of 685720 is 27586.

685720 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (685717) and next prime (685723).

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (685723) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8641 + ... + 8719.

It is an arithmetic number, because the mean of its divisors is an integer number (28800).

2⁶⁸⁵⁷²⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 685720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (921600).

685720 is an abundant number, since it is smaller than the sum of its proper divisors (1157480).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

685720 is a wasteful number, since it uses less digits than its factorization.

685720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128 (or 124 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 28.

The square root of 685720 is about 828.0821215314. The cubic root of 685720 is about 88.1824726116.

The spelling of 685720 in words is "six hundred eighty-five thousand, seven hundred twenty".