One billion is a numerical value represented by the digit 1 followed by nine zeros, or 1,000,000,000. It is a significant milestone in counting and is often used to describe large quantities, such as populations or financial figures. For example, the population of the world is estimated to be over seven billion. In terms of time, one billion seconds is approximately 31.7 years. This means that if someone were to count to one billion, it would take them a very long time—around 31.7 years of continuous counting! This illustrates just how large the number truly is in everyday contexts.