1. **State the problem:** Find the least common multiple (LCM) of the single number 123456789. 2. **Understand the concept:** The LCM of a single number is the number itself because the LCM is the smallest positive integer divisible by all numbers in the set. 3. **Apply the rule:** Since there is only one number, the LCM is simply 123456789. **Final answer:** $$\text{LCM}(123456789) = 123456789$$