In addition we can say of the number 42 that it is even
42 is an even number, as it is divisible by 2 : 42/2 = 21
The factors for 42 are all the numbers between -42 and 42 , which divide 42 without leaving any remainder. Since 42 divided by -42 is an integer, -42 is a factor of 42 .
Since 42 divided by -42 is a whole number, -42 is a factor of 42
Since 42 divided by -21 is a whole number, -21 is a factor of 42
Since 42 divided by -14 is a whole number, -14 is a factor of 42
Since 42 divided by -7 is a whole number, -7 is a factor of 42
Since 42 divided by -6 is a whole number, -6 is a factor of 42
Since 42 divided by -3 is a whole number, -3 is a factor of 42
Since 42 divided by -2 is a whole number, -2 is a factor of 42
Since 42 divided by -1 is a whole number, -1 is a factor of 42
Multiples of 42 are all integers divisible by 42 , i.e. the remainder of the full division by 42 is zero. There are infinite multiples of 42. The smallest multiples of 42 are:
It is possible to determine using mathematical techniques whether an integer is prime or not.
for 42, the answer is: No, 42 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 42). 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 6.481 ). 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.
Previous prime number: 41
Next prime number: 43