The list of all positive divisors (that is, the list of all integers that divide 22) is as follows :
Accordingly:
80 is multiplo of 1
80 is multiplo of 2
80 is multiplo of 4
80 is multiplo of 5
80 is multiplo of 8
80 is multiplo of 10
80 is multiplo of 16
80 is multiplo of 20
80 is multiplo of 40
80 has 9 positive divisors
In addition we can say of the number 80 that it is even
80 is an even number, as it is divisible by 2 : 80/2 = 40
The factors for 80 are all the numbers between -80 and 80 , which divide 80 without leaving any remainder. Since 80 divided by -80 is an integer, -80 is a factor of 80 .
Since 80 divided by -80 is a whole number, -80 is a factor of 80
Since 80 divided by -40 is a whole number, -40 is a factor of 80
Since 80 divided by -20 is a whole number, -20 is a factor of 80
Since 80 divided by -16 is a whole number, -16 is a factor of 80
Since 80 divided by -10 is a whole number, -10 is a factor of 80
Since 80 divided by -8 is a whole number, -8 is a factor of 80
Since 80 divided by -5 is a whole number, -5 is a factor of 80
Since 80 divided by -4 is a whole number, -4 is a factor of 80
Since 80 divided by -2 is a whole number, -2 is a factor of 80
Since 80 divided by -1 is a whole number, -1 is a factor of 80
Since 80 divided by 1 is a whole number, 1 is a factor of 80
Since 80 divided by 2 is a whole number, 2 is a factor of 80
Since 80 divided by 4 is a whole number, 4 is a factor of 80
Since 80 divided by 5 is a whole number, 5 is a factor of 80
Since 80 divided by 8 is a whole number, 8 is a factor of 80
Since 80 divided by 10 is a whole number, 10 is a factor of 80
Since 80 divided by 16 is a whole number, 16 is a factor of 80
Since 80 divided by 20 is a whole number, 20 is a factor of 80
Since 80 divided by 40 is a whole number, 40 is a factor of 80
Multiples of 80 are all integers divisible by 80 , i.e. the remainder of the full division by 80 is zero. There are infinite multiples of 80. The smallest multiples of 80 are:
0 : in fact, 0 is divisible by any integer, so it is also a multiple of 80 since 0 × 80 = 0
80 : in fact, 80 is a multiple of itself, since 80 is divisible by 80 (it was 80 / 80 = 1, so the rest of this division is zero)
etc.
It is possible to determine using mathematical techniques whether an integer is prime or not.
for 80, the answer is: No, 80 is not a prime number.
To know the primality of an integer, we can use several algorithms. The most naive is to try all divisors below the number you want to know if it is prime (in our case 80). We can already eliminate even numbers bigger than 2 (then 4 , 6 , 8 ...). Besides, we can stop at the square root of the number in question (here 8.944 ). Historically, the Eratosthenes screen (which dates back to Antiquity) uses this technique relatively effectively.
More modern techniques include the Atkin screen, probabilistic tests, or the cyclotomic test.
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