491is an odd number,as it is not divisible by 2
The factors for 491 are all the numbers between -491 and 491 , which divide 491 without leaving any remainder. Since 491 divided by -491 is an integer, -491 is a factor of 491 .
Since 491 divided by -491 is a whole number, -491 is a factor of 491
Since 491 divided by -1 is a whole number, -1 is a factor of 491
Multiples of 491 are all integers divisible by 491 , i.e. the remainder of the full division by 491 is zero. There are infinite multiples of 491. The smallest multiples of 491 are:
It is possible to determine using mathematical techniques whether an integer is prime or not.
for 491, the answer is: yes, 491 is a prime number because it only has two different divisors: 1 and itself (491).
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 491). 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 22.159 ). 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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Next prime number: 499