GCF and LCM of 14 and 21
The greatest common factor and least common multiple of 14 and 21.
GCF of 14 and 21
7
LCM of 14 and 21
42
How it works
Break each number into its prime factors:
- 14 = 2 × 7
- 21 = 3 × 7
The GCF (7) multiplies the primes both share, at the lowest power each appears. The LCM (42) multiplies every prime that appears in either number, at the highest power — which is also 14 × 21 ÷ 7 = 42.
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Frequently asked questions
What is the GCF of 14 and 21?+
The greatest common factor (GCF) of 14 and 21 is 7 — the largest number that divides both 14 and 21 with no remainder.
What is the LCM of 14 and 21?+
The least common multiple (LCM) of 14 and 21 is 42 — the smallest number that both 14 and 21 divide into. It equals 14 × 21 ÷ GCF = 294 ÷ 7 = 42.