Number 685 is an integer that follows 684 and precedes 686. It is an odd number and can be expressed as the sum of two prime numbers, specifically 683 and 2. In mathematics, it is often analyzed in various contexts, such as number theory and sequences. In terms of its properties, 685 can be factored into prime components, which are 5 and 137. This means that 685 is a composite number, as it has divisors other than 1 and itself. It can also be represented in different numeral systems, such as binary (1010101101) and hexadecimal (2AF).