How many years are in 123456789 seconds?

To convert seconds to years, we need to divide the total number of seconds by the number of seconds in a year. There are 60 seconds in a minute, 60 minutes in an hour, and 24 hours in a day, which gives us 60 x 60 x 24 = 86,400 seconds in a day. Multiplying this by 365 days in a year, we get 31,536,000 seconds in a year. Dividing 123,456,789 seconds by 31,536,000 seconds in a year gives us approximately 3.91 years.