What is the LCM of 21 and 77?

"Least Common Multiple" Calculator

What's the Least Common Multiple (LCM) of 21 and 77?

Answer: LCM of 21 and 77 is 231

(Two hundred thirty-one)

Finding LCM for 21 and 77 using GCF's of these numbers

The first method to find LCM for numbers 21 and 77 is to find Greatest Common Factor (GCF) of these numbers. Here's the formula:

LCM = (Number1 × Number2) ÷ GCF

GCF of numbers 21 and 77 is 7, so

LCM = (21 × 77) ÷ 7

LCM = 1617 ÷ 7

LCM = 231

Finding LCM for 21 and 77 by Listing Multiples

The second method to find LCM for numbers 21 and 77 is to list out the common multiples for both nubmers and pick the first which matching:

Multiples of 21: 21, 42, 63, 84, 105, 126, 147, 168, 189, 210, 231, 252, 273

Multiples of 77: 77, 154, 231, 308, 385

So the LCM for 21 and 77 is 231

Finding LCM for 21 and 77 by Prime Factorization

Another method to find LCM for numbers 21 and 77 is to list all Prime Factors for both numbers and multiply the highest exponent prime factors:

All Prime Factors of 21: 3, 7 (exponent form: 3¹, 7¹)

All Prime Factors of 77: 7, 11 (exponent form: 7¹, 11¹)

3¹ × 7¹ × 11¹ = 231

About "Least Common Multiple" Calculator

This calculator will help you find the Least Common Multiple (LCM) of two numbers. For example, it can help you find out what's the Least Common Multiple (LCM) of 21 and 77? (The answer is: 231). Select the first number (e.g. '21') and the second number (e.g. '77'). After that hit the 'Calculate' button.

Least Common Multiple (LCM) also known as the Lowest Common Multiple or Smallest Common Multiple of 2 numbers - it is the smallest positive integer that is divisible by both numbers

"Least Common Multiple" Calculator

LCM Table

Number 1	Number 2	LCM
6	77	462
7	77	77
8	77	616
9	77	693
10	77	770
11	77	77
12	77	924
13	77	1001
14	77	154
15	77	1155
16	77	1232
17	77	1309
18	77	1386
19	77	1463
20	77	1540
21	77	231
22	77	154
23	77	1771
24	77	1848
25	77	1925
26	77	2002
27	77	2079
28	77	308
29	77	2233
30	77	2310
31	77	2387
32	77	2464
33	77	231
34	77	2618
35	77	385

LCM for 21 and 77

"Least Common Multiple" Calculator

What's the Least Common Multiple (LCM) of 21 and 77?

Finding LCM for 21 and 77 using GCF's of these numbers

Finding LCM for 21 and 77 by Listing Multiples

Finding LCM for 21 and 77 by Prime Factorization

See Also

About "Least Common Multiple" Calculator

"Least Common Multiple" Calculator

LCM Table

FAQ

What's the Least Common Multiple (LCM) of 21 and 77?

See Also