In addition we can say of the number 428 that it is even
428 is an even number, as it is divisible by 2 : 428/2 = 214
The factors for 428 are all the numbers between -428 and 428 , which divide 428 without leaving any remainder. Since 428 divided by -428 is an integer, -428 is a factor of 428 .
Since 428 divided by -428 is a whole number, -428 is a factor of 428
Since 428 divided by -214 is a whole number, -214 is a factor of 428
Since 428 divided by -107 is a whole number, -107 is a factor of 428
Since 428 divided by -4 is a whole number, -4 is a factor of 428
Since 428 divided by -2 is a whole number, -2 is a factor of 428
Since 428 divided by -1 is a whole number, -1 is a factor of 428
Multiples of 428 are all integers divisible by 428 , i.e. the remainder of the full division by 428 is zero. There are infinite multiples of 428. The smallest multiples of 428 are:
It is possible to determine using mathematical techniques whether an integer is prime or not.
for 428, the answer is: No, 428 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 428). 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 20.688 ). 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: 421
Next prime number: 431