The list of all positive divisors (that is, the list of all integers that divide 22) is as follows :
1990 is multiplo of 1
1990 is multiplo of 2
1990 is multiplo of 5
1990 is multiplo of 10
1990 is multiplo of 199
1990 is multiplo of 398
1990 is multiplo of 995
1990 has 7 positive divisors
In addition we can say of the number 1990 that it is even
1990 is an even number, as it is divisible by 2 : 1990/2 = 995
The factors for 1990 are all the numbers between -1990 and 1990 , which divide 1990 without leaving any remainder. Since 1990 divided by -1990 is an integer, -1990 is a factor of 1990 .
Since 1990 divided by -1990 is a whole number, -1990 is a factor of 1990
Since 1990 divided by -995 is a whole number, -995 is a factor of 1990
Since 1990 divided by -398 is a whole number, -398 is a factor of 1990
Since 1990 divided by -199 is a whole number, -199 is a factor of 1990
Since 1990 divided by -10 is a whole number, -10 is a factor of 1990
Since 1990 divided by -5 is a whole number, -5 is a factor of 1990
Since 1990 divided by -2 is a whole number, -2 is a factor of 1990
Since 1990 divided by -1 is a whole number, -1 is a factor of 1990
Multiples of 1990 are all integers divisible by 1990 , i.e. the remainder of the full division by 1990 is zero. There are infinite multiples of 1990. The smallest multiples of 1990 are:
It is possible to determine using mathematical techniques whether an integer is prime or not.
for 1990, the answer is: No, 1990 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 1990). 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 44.609 ). 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: 1987
Next prime number: 1993