To find all the divisors of the number 39,960:
- 1. Decompose the number into prime factors.
- See how you can find out how many factors (divisors) the number has, without actually calculating them.
- 2. Multiply the prime factors in all their unique combinations, that yield different results.
1. Carry out the prime factorization of the number 39,960:
The prime factorization of a number: finding the prime numbers that multiply together to make that number.
39,960 = 23 × 33 × 5 × 37
39,960 is not a prime number but a composite one.
- Prime number: a natural number that is divisible (divided evenly) only by 1 and itself. A prime number has exactly two factors: 1 and the number 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), ...
- Composite number: 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), ...
How to count the number of factors of a number?
Without actually finding the factors
- If a number N is prime factorized as:
N = am × bk × cz
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) × (3 + 1) × (1 + 1) × (1 + 1) = 4 × 4 × 2 × 2 = 64
But to actually calculate the factors, see below...
2. Multiply the prime factors of the number 39,960
- Multiply the prime factors involved in the prime factorization of the number in all their unique combinations, that give different results.
- Also consider the exponents of these prime factors.
- 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 factors (divisors).
neither prime nor composite =
1
prime factor =
2
prime factor =
3
composite factor = 2
2 =
4
prime factor =
5
composite factor = 2 × 3 =
6
composite factor = 2
3 =
8
composite factor = 3
2 =
9
composite factor = 2 × 5 =
10
composite factor = 2
2 × 3 =
12
composite factor = 3 × 5 =
15
composite factor = 2 × 3
2 =
18
composite factor = 2
2 × 5 =
20
composite factor = 2
3 × 3 =
24
composite factor = 3
3 =
27
composite factor = 2 × 3 × 5 =
30
composite factor = 2
2 × 3
2 =
36
prime factor =
37
composite factor = 2
3 × 5 =
40
composite factor = 3
2 × 5 =
45
composite factor = 2 × 3
3 =
54
composite factor = 2
2 × 3 × 5 =
60
composite factor = 2
3 × 3
2 =
72
composite factor = 2 × 37 =
74
composite factor = 2 × 3
2 × 5 =
90
composite factor = 2
2 × 3
3 =
108
composite factor = 3 × 37 =
111
composite factor = 2
3 × 3 × 5 =
120
composite factor = 3
3 × 5 =
135
composite factor = 2
2 × 37 =
148
composite factor = 2
2 × 3
2 × 5 =
180
composite factor = 5 × 37 =
185
This list continues below...
... This list continues from above
composite factor = 2
3 × 3
3 =
216
composite factor = 2 × 3 × 37 =
222
composite factor = 2 × 3
3 × 5 =
270
composite factor = 2
3 × 37 =
296
composite factor = 3
2 × 37 =
333
composite factor = 2
3 × 3
2 × 5 =
360
composite factor = 2 × 5 × 37 =
370
composite factor = 2
2 × 3 × 37 =
444
composite factor = 2
2 × 3
3 × 5 =
540
composite factor = 3 × 5 × 37 =
555
composite factor = 2 × 3
2 × 37 =
666
composite factor = 2
2 × 5 × 37 =
740
composite factor = 2
3 × 3 × 37 =
888
composite factor = 3
3 × 37 =
999
composite factor = 2
3 × 3
3 × 5 =
1,080
composite factor = 2 × 3 × 5 × 37 =
1,110
composite factor = 2
2 × 3
2 × 37 =
1,332
composite factor = 2
3 × 5 × 37 =
1,480
composite factor = 3
2 × 5 × 37 =
1,665
composite factor = 2 × 3
3 × 37 =
1,998
composite factor = 2
2 × 3 × 5 × 37 =
2,220
composite factor = 2
3 × 3
2 × 37 =
2,664
composite factor = 2 × 3
2 × 5 × 37 =
3,330
composite factor = 2
2 × 3
3 × 37 =
3,996
composite factor = 2
3 × 3 × 5 × 37 =
4,440
composite factor = 3
3 × 5 × 37 =
4,995
composite factor = 2
2 × 3
2 × 5 × 37 =
6,660
composite factor = 2
3 × 3
3 × 37 =
7,992
composite factor = 2 × 3
3 × 5 × 37 =
9,990
composite factor = 2
3 × 3
2 × 5 × 37 =
13,320
composite factor = 2
2 × 3
3 × 5 × 37 =
19,980
composite factor = 2
3 × 3
3 × 5 × 37 =
39,960
64 factors (divisors)
What times what is 39,960?
What number multiplied by what number equals 39,960?
All the combinations of any two natural numbers whose product equals 39,960.
1 × 39,960 = 39,960
2 × 19,980 = 39,960
3 × 13,320 = 39,960
4 × 9,990 = 39,960
5 × 7,992 = 39,960
6 × 6,660 = 39,960
8 × 4,995 = 39,960
9 × 4,440 = 39,960
10 × 3,996 = 39,960
12 × 3,330 = 39,960
15 × 2,664 = 39,960
18 × 2,220 = 39,960
20 × 1,998 = 39,960
24 × 1,665 = 39,960
27 × 1,480 = 39,960
30 × 1,332 = 39,960
36 × 1,110 = 39,960
37 × 1,080 = 39,960
40 × 999 = 39,960
45 × 888 = 39,960
54 × 740 = 39,960
60 × 666 = 39,960
72 × 555 = 39,960
74 × 540 = 39,960
90 × 444 = 39,960
108 × 370 = 39,960
111 × 360 = 39,960
120 × 333 = 39,960
135 × 296 = 39,960
148 × 270 = 39,960
180 × 222 = 39,960
185 × 216 = 39,960
32 unique multiplications The final answer:
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