71is an odd number,as it is not divisible by 2
The factors for 71 are all the numbers between -71 and 71 , which divide 71 without leaving any remainder. Since 71 divided by -71 is an integer, -71 is a factor of 71 .
Since 71 divided by -71 is a whole number, -71 is a factor of 71
Since 71 divided by -1 is a whole number, -1 is a factor of 71
Since 71 divided by 1 is a whole number, 1 is a factor of 71
Multiples of 71 are all integers divisible by 71 , i.e. the remainder of the full division by 71 is zero. There are infinite multiples of 71. The smallest multiples of 71 are:
0 : in fact, 0 is divisible by any integer, so it is also a multiple of 71 since 0 × 71 = 0
71 : in fact, 71 is a multiple of itself, since 71 is divisible by 71 (it was 71 / 71 = 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 71, the answer is: yes, 71 is a prime number because it only has two different divisors: 1 and itself (71).
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 71). 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 8.426 ). 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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