1. Move the decimal point: Start with 6607900.0 (the decimal point is implied at the end of a whole number). Move the decimal point to the left until you have a number between 1 and 10. You'll move it six places to the left, resulting in 6.607900.

2. Count the moves: You moved the decimal point six places to the left.

3. Write the number in scientific notation:

* The number between 1 and 10: 6.607900

* Multiply by 10 raised to the power of the number of places you moved the decimal (and make it positive if you moved the decimal to the left): x 10⁶

Therefore, 6607900 in scientific notation is 6.607900 x 10⁶.