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Prime Factorization of 21

"Prime Factorization" Calculator

What is the Prime Factorization of 21?

Answer

Prime Factors of 21:

3, 7

21 = 3 × 7 · composite · 4 factors

Division ladder

21	3
7	7
1

Left: what is left; right: the smallest prime that divides it; 1 at the bottom.

Second way — factor tree

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See Also

Factors of a Number - List all Factors and Factor Pairs of a Number
Prime Number Checker - Find out whether a given number is Prime or not
Prime Numbers List - List of all Prime Numbers - how many Prime numbers are between

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Prime factors of 21. Prime factorization of 21: 3 × 7. Break down any number into a product of prime factors online.

https://calculat.io/en/number/prime-factors-of/21/generated.jpg

Prime Factorization Table

Number	Prime Factors
6	2, 3
7	7
8	2³
9	3²
10	2, 5
11	11
12	2² × 3
13	13
14	2, 7
15	3, 5
16	2⁴
17	17
18	2 × 3²
19	19
20	2² × 5
21	3, 7
22	2, 11
23	23
24	2³ × 3
25	5²
26	2, 13
27	3³
28	2² × 7
29	29
30	2, 3, 5
31	31
32	2⁵
33	3, 11
34	2, 17
35	5, 7

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FAQ

What is the Prime Factorization of 21?

Prime Factors of 21: 3, 7

How many prime factors does 21 have?

Number 21 has 2 prime factors, all different.

How can you check the prime factorization of 21?

Multiply the factors back together: 3 × 7 = 21. Every factor is prime, so nothing splits any further and this decomposition is the only one that exists.