To express each of the numbers in scientific notation, we need to write them in the form of \( a \times 10^n \), where \( 1 \leq a < 10 \) and \( n \) is an integer.
-
For 86,659,000:
- Move the decimal point 7 places to the left.
- \( 86,659,000 = 8.6659 \times 10^7 \)
-
For 867,450,000:
- Move the decimal point 8 places to the left.
- \( 867,450,000 = 8.6745 \times 10^8 \)
-
For 86,423,000:
- Move the decimal point 7 places to the left.
- \( 86,423,000 = 8.6423 \times 10^7 \)
Now, let's compare the numbers in scientific notation:
- \( 8.6659 \times 10^7 \) (for 86,659,000)
- \( 8.6745 \times 10^8 \) (for 867,450,000)
- \( 8.6423 \times 10^7 \) (for 86,423,000)
The powers of 10 indicate the scale of the numbers:
- \( 8.6659 \times 10^7 \) and \( 8.6423 \times 10^7 \) are both multiplied by \( 10^7 \), while \( 8.6745 \times 10^8 \) is multiplied by \( 10^8 \), making it much larger.
Among \( 8.6659 \times 10^7 \) and \( 8.6423 \times 10^7 \):
- \( 8.6423 < 8.6659 \)
Thus, among the three numbers, the number with the least value is 86,423,000, which in scientific notation is:
\[ \boxed{8.6423 \times 10^7} \]