To find all the divisors of the number 791,440:
- 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 791,440:
The prime factorization of a number: finding the prime numbers that multiply together to make that number.
791,440 = 24 × 5 × 13 × 761
791,440 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 = (4 + 1) × (1 + 1) × (1 + 1) × (1 + 1) = 5 × 2 × 2 × 2 = 40
But to actually calculate the factors, see below...
2. Multiply the prime factors of the number 791,440
- 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
composite factor = 2
2 =
4
prime factor =
5
composite factor = 2
3 =
8
composite factor = 2 × 5 =
10
prime factor =
13
composite factor = 2
4 =
16
composite factor = 2
2 × 5 =
20
composite factor = 2 × 13 =
26
composite factor = 2
3 × 5 =
40
composite factor = 2
2 × 13 =
52
composite factor = 5 × 13 =
65
composite factor = 2
4 × 5 =
80
composite factor = 2
3 × 13 =
104
composite factor = 2 × 5 × 13 =
130
composite factor = 2
4 × 13 =
208
composite factor = 2
2 × 5 × 13 =
260
composite factor = 2
3 × 5 × 13 =
520
prime factor =
761
This list continues below...
... This list continues from above
composite factor = 2
4 × 5 × 13 =
1,040
composite factor = 2 × 761 =
1,522
composite factor = 2
2 × 761 =
3,044
composite factor = 5 × 761 =
3,805
composite factor = 2
3 × 761 =
6,088
composite factor = 2 × 5 × 761 =
7,610
composite factor = 13 × 761 =
9,893
composite factor = 2
4 × 761 =
12,176
composite factor = 2
2 × 5 × 761 =
15,220
composite factor = 2 × 13 × 761 =
19,786
composite factor = 2
3 × 5 × 761 =
30,440
composite factor = 2
2 × 13 × 761 =
39,572
composite factor = 5 × 13 × 761 =
49,465
composite factor = 2
4 × 5 × 761 =
60,880
composite factor = 2
3 × 13 × 761 =
79,144
composite factor = 2 × 5 × 13 × 761 =
98,930
composite factor = 2
4 × 13 × 761 =
158,288
composite factor = 2
2 × 5 × 13 × 761 =
197,860
composite factor = 2
3 × 5 × 13 × 761 =
395,720
composite factor = 2
4 × 5 × 13 × 761 =
791,440
40 factors (divisors)
What times what is 791,440?
What number multiplied by what number equals 791,440?
All the combinations of any two natural numbers whose product equals 791,440.
1 × 791,440 = 791,440
2 × 395,720 = 791,440
4 × 197,860 = 791,440
5 × 158,288 = 791,440
8 × 98,930 = 791,440
10 × 79,144 = 791,440
13 × 60,880 = 791,440
16 × 49,465 = 791,440
20 × 39,572 = 791,440
26 × 30,440 = 791,440
40 × 19,786 = 791,440
52 × 15,220 = 791,440
65 × 12,176 = 791,440
80 × 9,893 = 791,440
104 × 7,610 = 791,440
130 × 6,088 = 791,440
208 × 3,805 = 791,440
260 × 3,044 = 791,440
520 × 1,522 = 791,440
761 × 1,040 = 791,440
20 unique multiplications The final answer:
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