To find all the divisors of the number 90,720:
- 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 90,720:
The prime factorization of a number: finding the prime numbers that multiply together to make that number.
90,720 = 25 × 34 × 5 × 7
90,720 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 = (5 + 1) × (4 + 1) × (1 + 1) × (1 + 1) = 6 × 5 × 2 × 2 = 120
But to actually calculate the factors, see below...
2. Multiply the prime factors of the number 90,720
- 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
prime factor =
7
composite factor = 2
3 =
8
composite factor = 3
2 =
9
composite factor = 2 × 5 =
10
composite factor = 2
2 × 3 =
12
composite factor = 2 × 7 =
14
composite factor = 3 × 5 =
15
composite factor = 2
4 =
16
composite factor = 2 × 3
2 =
18
composite factor = 2
2 × 5 =
20
composite factor = 3 × 7 =
21
composite factor = 2
3 × 3 =
24
composite factor = 3
3 =
27
composite factor = 2
2 × 7 =
28
composite factor = 2 × 3 × 5 =
30
composite factor = 2
5 =
32
composite factor = 5 × 7 =
35
composite factor = 2
2 × 3
2 =
36
composite factor = 2
3 × 5 =
40
composite factor = 2 × 3 × 7 =
42
composite factor = 3
2 × 5 =
45
composite factor = 2
4 × 3 =
48
composite factor = 2 × 3
3 =
54
composite factor = 2
3 × 7 =
56
composite factor = 2
2 × 3 × 5 =
60
composite factor = 3
2 × 7 =
63
composite factor = 2 × 5 × 7 =
70
composite factor = 2
3 × 3
2 =
72
composite factor = 2
4 × 5 =
80
composite factor = 3
4 =
81
composite factor = 2
2 × 3 × 7 =
84
composite factor = 2 × 3
2 × 5 =
90
composite factor = 2
5 × 3 =
96
composite factor = 3 × 5 × 7 =
105
composite factor = 2
2 × 3
3 =
108
composite factor = 2
4 × 7 =
112
composite factor = 2
3 × 3 × 5 =
120
composite factor = 2 × 3
2 × 7 =
126
composite factor = 3
3 × 5 =
135
composite factor = 2
2 × 5 × 7 =
140
composite factor = 2
4 × 3
2 =
144
composite factor = 2
5 × 5 =
160
composite factor = 2 × 3
4 =
162
composite factor = 2
3 × 3 × 7 =
168
composite factor = 2
2 × 3
2 × 5 =
180
composite factor = 3
3 × 7 =
189
composite factor = 2 × 3 × 5 × 7 =
210
composite factor = 2
3 × 3
3 =
216
composite factor = 2
5 × 7 =
224
composite factor = 2
4 × 3 × 5 =
240
composite factor = 2
2 × 3
2 × 7 =
252
composite factor = 2 × 3
3 × 5 =
270
composite factor = 2
3 × 5 × 7 =
280
composite factor = 2
5 × 3
2 =
288
This list continues below...
... This list continues from above
composite factor = 3
2 × 5 × 7 =
315
composite factor = 2
2 × 3
4 =
324
composite factor = 2
4 × 3 × 7 =
336
composite factor = 2
3 × 3
2 × 5 =
360
composite factor = 2 × 3
3 × 7 =
378
composite factor = 3
4 × 5 =
405
composite factor = 2
2 × 3 × 5 × 7 =
420
composite factor = 2
4 × 3
3 =
432
composite factor = 2
5 × 3 × 5 =
480
composite factor = 2
3 × 3
2 × 7 =
504
composite factor = 2
2 × 3
3 × 5 =
540
composite factor = 2
4 × 5 × 7 =
560
composite factor = 3
4 × 7 =
567
composite factor = 2 × 3
2 × 5 × 7 =
630
composite factor = 2
3 × 3
4 =
648
composite factor = 2
5 × 3 × 7 =
672
composite factor = 2
4 × 3
2 × 5 =
720
composite factor = 2
2 × 3
3 × 7 =
756
composite factor = 2 × 3
4 × 5 =
810
composite factor = 2
3 × 3 × 5 × 7 =
840
composite factor = 2
5 × 3
3 =
864
composite factor = 3
3 × 5 × 7 =
945
composite factor = 2
4 × 3
2 × 7 =
1,008
composite factor = 2
3 × 3
3 × 5 =
1,080
composite factor = 2
5 × 5 × 7 =
1,120
composite factor = 2 × 3
4 × 7 =
1,134
composite factor = 2
2 × 3
2 × 5 × 7 =
1,260
composite factor = 2
4 × 3
4 =
1,296
composite factor = 2
5 × 3
2 × 5 =
1,440
composite factor = 2
3 × 3
3 × 7 =
1,512
composite factor = 2
2 × 3
4 × 5 =
1,620
composite factor = 2
4 × 3 × 5 × 7 =
1,680
composite factor = 2 × 3
3 × 5 × 7 =
1,890
composite factor = 2
5 × 3
2 × 7 =
2,016
composite factor = 2
4 × 3
3 × 5 =
2,160
composite factor = 2
2 × 3
4 × 7 =
2,268
composite factor = 2
3 × 3
2 × 5 × 7 =
2,520
composite factor = 2
5 × 3
4 =
2,592
composite factor = 3
4 × 5 × 7 =
2,835
composite factor = 2
4 × 3
3 × 7 =
3,024
composite factor = 2
3 × 3
4 × 5 =
3,240
composite factor = 2
5 × 3 × 5 × 7 =
3,360
composite factor = 2
2 × 3
3 × 5 × 7 =
3,780
composite factor = 2
5 × 3
3 × 5 =
4,320
composite factor = 2
3 × 3
4 × 7 =
4,536
composite factor = 2
4 × 3
2 × 5 × 7 =
5,040
composite factor = 2 × 3
4 × 5 × 7 =
5,670
composite factor = 2
5 × 3
3 × 7 =
6,048
composite factor = 2
4 × 3
4 × 5 =
6,480
composite factor = 2
3 × 3
3 × 5 × 7 =
7,560
composite factor = 2
4 × 3
4 × 7 =
9,072
composite factor = 2
5 × 3
2 × 5 × 7 =
10,080
composite factor = 2
2 × 3
4 × 5 × 7 =
11,340
composite factor = 2
5 × 3
4 × 5 =
12,960
composite factor = 2
4 × 3
3 × 5 × 7 =
15,120
composite factor = 2
5 × 3
4 × 7 =
18,144
composite factor = 2
3 × 3
4 × 5 × 7 =
22,680
composite factor = 2
5 × 3
3 × 5 × 7 =
30,240
composite factor = 2
4 × 3
4 × 5 × 7 =
45,360
composite factor = 2
5 × 3
4 × 5 × 7 =
90,720
120 factors (divisors)
What times what is 90,720?
What number multiplied by what number equals 90,720?
All the combinations of any two natural numbers whose product equals 90,720.
1 × 90,720 = 90,720
2 × 45,360 = 90,720
3 × 30,240 = 90,720
4 × 22,680 = 90,720
5 × 18,144 = 90,720
6 × 15,120 = 90,720
7 × 12,960 = 90,720
8 × 11,340 = 90,720
9 × 10,080 = 90,720
10 × 9,072 = 90,720
12 × 7,560 = 90,720
14 × 6,480 = 90,720
15 × 6,048 = 90,720
16 × 5,670 = 90,720
18 × 5,040 = 90,720
20 × 4,536 = 90,720
21 × 4,320 = 90,720
24 × 3,780 = 90,720
27 × 3,360 = 90,720
28 × 3,240 = 90,720
30 × 3,024 = 90,720
32 × 2,835 = 90,720
35 × 2,592 = 90,720
36 × 2,520 = 90,720
40 × 2,268 = 90,720
42 × 2,160 = 90,720
45 × 2,016 = 90,720
48 × 1,890 = 90,720
54 × 1,680 = 90,720
56 × 1,620 = 90,720
60 × 1,512 = 90,720
63 × 1,440 = 90,720
70 × 1,296 = 90,720
72 × 1,260 = 90,720
80 × 1,134 = 90,720
81 × 1,120 = 90,720
84 × 1,080 = 90,720
90 × 1,008 = 90,720
96 × 945 = 90,720
105 × 864 = 90,720
108 × 840 = 90,720
112 × 810 = 90,720
120 × 756 = 90,720
126 × 720 = 90,720
135 × 672 = 90,720
140 × 648 = 90,720
144 × 630 = 90,720
160 × 567 = 90,720
162 × 560 = 90,720
168 × 540 = 90,720
180 × 504 = 90,720
189 × 480 = 90,720
210 × 432 = 90,720
216 × 420 = 90,720
224 × 405 = 90,720
240 × 378 = 90,720
252 × 360 = 90,720
270 × 336 = 90,720
280 × 324 = 90,720
288 × 315 = 90,720
60 unique multiplications The final answer:
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