* Seconds in a minute: 60

* Minutes in an hour: 60

* Hours in a day: 24

* Days in a year: 365.25 (accounting for leap years)

* Years in a century: 100

Calculations:

1. Seconds in a year: 60 seconds/minute * 60 minutes/hour * 24 hours/day * 365.25 days/year = 31,557,600 seconds

2. Seconds in a century: 31,557,600 seconds/year * 100 years/century = 3,155,760,000 seconds

3. Nanoseconds in a century: 3,155,760,000 seconds/century * 1,000,000,000 nanoseconds/second = 3.15576 x 10^16 nanoseconds

Therefore, there are approximately 31,557,600,000,000,000 nanoseconds in a century.