3.868 * 10⁹
Converting numbers to scientific notation is expressing in the form a * 10ᵇ such that 0 < a < 10. In other words, a should only have one digit to the left of the decimal point that is NOT 0.
In the given, it is not as obvious but the decimal point is at the end.
= 3.868 * 10ᵇ
Since the number is rather large, and we moved our decimal point to the left 9 times, our exponent is positive 9.
= 3.868 * 10⁹