The prime factorization of 399 is:
$$ 399 = 3\cdot7\cdot19 $$Prime factorization can be nicely visualized by creating a factorization tree.
| 399 can be written as 3 × 133. |
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| 133 can be written as 7 × 19. |
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| The end nodes are the prime factors of the number 399. |
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