Earth is about 4.54 billion years old. The average day length has increased over time due to tidal friction. Early Earth rotated much faster, estimated 5 to 6 hours per day.

Using a rough integration of changing day length over geologic time:

~4.5 billion years ago: ~5 h days ~1,752 days per year

Today: 24 h days 365 days per year

Average across history: about 900–1000 days per year

Total rotations ≈ average days/year × years = (≈950) × (4.54 × 109) ≈ 4.3 × 1012 rotations.