Chapter 2 - Real Numbers - Chapters 1-2 Cumulative Review Problem Set - Page 91: 24

$3\times3\times17$

First, we divide 153 by the prime number 3. This results in the number 51. 51 can further be divided by 3 to obtain 17, which is also a prime number. Therefore, as a product of prime factors, 153 can be written as: $153=3\times51=3\times3\times17$