Chapter 1, Equations and Inequalities - 1.1 - Apply Properties of Real Numbers - Guided Practice for Examples 5 and 6 - Page 5: 14

$504921600 seconds$

We know that $1$ year equals $365.25$ days. Thus $16 years=16\cdot365.25 days=5844 days$. We know that $1$ day equals $24\cdot60\cdot60=86400$ seconds. Thus $16 years=5844\cdot86400 seconds=504921600 seconds$