The scientific notation of $\text{123456789}$ is

Explanation:

In scientific notation:

1. The number is written in the form a×10^b , where a is a number between 1 and 10, and b is an integer.
2. For 123456789, move the decimal point 8 places to the left to make it a number between 1 and 10. This gives 1.23456789
3. Since the decimal point was moved 8 places, b=8

Thus, the correct answer is 1.23456789 × 10⁸.