Common Factors of 63,000 and 1,520. Calculator of Prime and Compound Divisors, if Any

What are the common factors (divisors) of the numbers 63,000 and 1,520?

The common factors of the numbers 63,000 and 1,520 are all the factors of their 'greatest common factor', gcf

Calculations:

Calculate all the (common) factors (divisors) of one or two numbers

Calculate the greatest (highest) common factor (divisor).
Follow the two steps below.

1. Perform the prime factorization of the two numbers:

The prime factorization of a number: finding the prime numbers that multiply together to make that number.

63,000 = 2³ × 3² × 5³ × 7
63,000 is not a prime number but a composite one.

1,520 = 2⁴ × 5 × 19
1,520 is not a prime number but a composite one.

Prime number: a natural number that is divisible only by 1 and itself. A prime number has exactly two factors: 1 and itself.
Examples of prime numbers: 2 (factors 1, 2), 3 (factors 1, 3), 5 (factors 1, 5), 7 (factors 1, 7), 11 (factors 1, 11), 13 (factors 1, 13), ...
A composite number is a natural number that has at least one factor other than 1 and itself. So it is neither a prime number nor 1.
Examples of composite numbers: 4 (it has 3 factors: 1, 2, 4), 6 (it has 4 factors: 1, 2, 3, 6), 8 (it has 4 factors: 1, 2, 4, 8), 9 (it has 3 factors: 1, 3, 9), 10 (it has 4 factors: 1, 2, 5, 10), 12 (it has 6 factors: 1, 2, 3, 4, 6, 12), ...
» Online calculator. Check whether a number is prime or not. The prime factorization of composite numbers (decomposition into prime factors)

2. Calculate the greatest (highest) common factor (divisor), gcf, hcf, gcd:

Multiply all the common prime factors, taken by their smallest exponents (the smallest powers).

gcf, hcf, gcd (63,000; 1,520) = 2³ × 5 = 40

» Online calculator. Calculate the greatest (highest) common factor (divisor)

How to count the number of factors of a number?

Without actually finding the factors

If a number N is prime factorized as:
N = a^m × b^k × c^z
where a, b, c are the prime factors and m, k, z are their exponents, natural numbers, ....
...
Then the number of factors of the number N can be calculated as:
n = (m + 1) × (k + 1) × (z + 1)
...
In our case, the number of factors is calculated as:
n = (3 + 1) × (1 + 1) = 4 × 2 = 8

But to actually calculate the factors, see below...

3. Multiply the prime factors of the 'gcf':

Multiply the prime factors involved in the prime factorization of the GCF in all their unique combinations, that give different results.
Also consider the exponents of the prime factors (example: 3² = 3 × 3 = 9).
Also add 1 to the list of factors (divisors). All the numbers are divisible by 1.

All the factors (divisors) are listed below - in ascending order

The list of factors (divisors):

Numbers other than 1 that are not prime factors are composite instead.

neither prime nor composite = 1

prime factor = 2

composite factor = 2² = 4

prime factor = 5

This list continues below...

... This list continues from above

composite factor = 2³ = 8

composite factor = 2 × 5 = 10

composite factor = 2² × 5 = 20

composite factor = 2³ × 5 = 40

8 common factors (divisors)

What times what is 40?
What number multiplied by what number equals 40?

All the combinations of any two natural numbers whose product equals 40.

1 × 40 = 40

2 × 20 = 40

4 × 10 = 40

5 × 8 = 40

4 unique multiplications

63,000 and 1,520 have 8 common factors (divisors):
1; 2; 4; 5; 8; 10; 20 and 40
out of which 2 prime factors: 2 and 5.
Numbers other than 1 that are not prime factors are composite instead.

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Factors (divisors), common factors (common divisors), the greatest common factor, GCF (also called the greatest common divisor, GCD, or the highest common factor, HCF)

If the number "t" is a factor (divisor) of the number "a" then in the prime factorization of "t" we will only encounter prime factors that also occur in the prime factorization of "a".
If there are exponents involved, the maximum value of an exponent for any base of a power that is found in the prime factorization of "t" (powers, or multiplicities) is at most equal to the exponent of the same base that is involved in the prime factorization of "a".
Hint: 2³ = 2 × 2 × 2 = 8. 2 is called the base and 3 is the exponent. 2³ is the power and 8 is the value of the power. We sometimes say that the number 2 is raised to the power of 3.

For example, 12 is a factor (divisor) of 120 - the remainder is zero when dividing 120 by 12.
Let's look at the prime factorization of both numbers and notice the bases and the exponents that occur in the prime factorization of both numbers:
12 = 2 × 2 × 3 = 2² × 3
120 = 2 × 2 × 2 × 3 × 5 = 2³ × 3 × 5
120 contains all the prime factors of 12, and all its bases' exponents are higher than those of 12.

If "t" is a common factor (divisor) of "a" and "b", then the prime factorization of "t" contains only the common prime factors involved in the prime factorizations of both "a" and "b".
If there are exponents involved, the maximum value of an exponent for any base of a power that is found in the prime factorization of "t" is at most equal to the minimum of the exponents of the same base that is involved in the prime factorization of both "a" and "b".

For example, 12 is the common factor of 48 and 360.
The remainder is zero when dividing either 48 or 360 by 12.
Here there are the prime factorizations of the three numbers, 12, 48 and 360:
12 = 2² × 3
48 = 2⁴ × 3
360 = 2³ × 3² × 5
Please note that 48 and 360 have more factors (divisors): 2, 3, 4, 6, 8, 12, 24. Among them, 24 is the greatest common factor, GCF (or the greatest common divisor, GCD, or the highest common factor, HCF) of 48 and 360.

The greatest common factor, GCF, of two numbers, "a" and "b", is the product of all the common prime factors involved in the prime factorizations of both "a" and "b", taken by the lowest exponents.
Based on this rule it is calculated the greatest common factor, GCF, (or the greatest common divisor GCD, HCF) of several numbers, as shown in the example below...

GCF, GCD (1,260; 3,024; 5,544) = ?
1,260 = 2² × 3²
3,024 = 2⁴ × 3² × 7
5,544 = 2³ × 3² × 7 × 11
The common prime factors are:
2 - its lowest exponent (multiplicity) is: min.(2; 3; 4) = 2
3 - its lowest exponent (multiplicity) is: min.(2; 2; 2) = 2
GCF, GCD (1,260; 3,024; 5,544) = 2² × 3² = 252

Coprime numbers:
If two numbers "a" and "b" have no other common factors (divisors) than 1, gfc, gcd, hcf (a; b) = 1, then the numbers "a" and "b" are called coprime (or relatively prime).

Factors of the GCF
If "a" and "b" are not coprime, then every common factor (divisor) of "a" and "b" is a also a factor (divisor) of the greatest common factor, GCF (greatest common divisor, GCD, highest common factor, HCF) of "a" and "b".