# Divisors of 31991

## Divisors of 31991

The list of all positive divisors (that is, the list of all integers that divide 22) is as follows :

• 1
• 31991

Accordingly:

31991 is multiplo of 1

31991 has 1 positive divisors

## Parity of 31991

31991is an odd number,as it is not divisible by 2

## The factors for 31991

The factors for 31991 are all the numbers between -31991 and 31991 , which divide 31991 without leaving any remainder. Since 31991 divided by -31991 is an integer, -31991 is a factor of 31991 .

Since 31991 divided by -31991 is a whole number, -31991 is a factor of 31991

Since 31991 divided by -1 is a whole number, -1 is a factor of 31991

Since 31991 divided by 1 is a whole number, 1 is a factor of 31991

## What are the multiples of 31991?

Multiples of 31991 are all integers divisible by 31991 , i.e. the remainder of the full division by 31991 is zero. There are infinite multiples of 31991. The smallest multiples of 31991 are:

0 : in fact, 0 is divisible by any integer, so it is also a multiple of 31991 since 0 × 31991 = 0

31991 : in fact, 31991 is a multiple of itself, since 31991 is divisible by 31991 (it was 31991 / 31991 = 1, so the rest of this division is zero)

63982: in fact, 63982 = 31991 × 2

95973: in fact, 95973 = 31991 × 3

127964: in fact, 127964 = 31991 × 4

159955: in fact, 159955 = 31991 × 5

etc.

## Is 31991 a prime number?

It is possible to determine using mathematical techniques whether an integer is prime or not.

for 31991, the answer is: yes, 31991 is a prime number because it only has two different divisors: 1 and itself (31991).

## How do you determine if a number is prime?

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 31991). 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 178.86 ). 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.