Is 21997 a prime number? What are the divisors of 21997?

## Is 21997 a prime number?

Yes, 21997 is a prime number.

Indeed, the definition of a prime numbers is to have only two distinct positive divisors, 1 and itself. A number is a divisor of another number when the remainder of Euclid’s division of the second one by the first one is zero. Concerning the number 21997, the only two divisors are 1 and 21997. Therefore 21997 is a prime number.

As a consequence, 21997 is only a multiple of 1 and 21997.

Since 21997 is a prime number, 21997 is also a deficient number, that is to say 21997 is a natural integer that is strictly larger than the sum of its proper divisors, i.e., the divisors of 21997 without 21997 itself (that is 1, by definition!).

## Parity of 21997

21997 is an odd number, because it is not evenly divisible by 2.

## Is 21997 a perfect square number?

A number is a perfect square (or a square number) if its square root is an integer; that is to say, it is the product of an integer with itself. Here, the square root of 21997 is about 148.314.

Thus, the square root of 21997 is not an integer, and therefore 21997 is not a square number.

Anyway, 21997 is a prime number, and a prime number cannot be a perfect square.

## What is the square number of 21997?

The square of a number (here 21997) is the result of the product of this number (21997) by itself (i.e., 21997 × 21997); the square of 21997 is sometimes called "raising 21997 to the power 2", or "21997 squared".

The square of 21997 is 483 868 009 because 21997 × 21997 = 219972 = 483 868 009.

As a consequence, 21997 is the square root of 483 868 009.

## Number of digits of 21997

21997 is a number with 5 digits.

## What are the multiples of 21997?

The multiples of 21997 are all integers evenly divisible by 21997, that is all numbers such that the remainder of the division by 21997 is zero. There are infinitely many multiples of 21997. The smallest multiples of 21997 are:

• 0: indeed, 0 is divisible by any natural number, and it is thus a multiple of 21997 too, since 0 × 21997 = 0
• 21997: indeed, 21997 is a multiple of itself, since 21997 is evenly divisible by 21997 (we have 21997 / 21997 = 1, so the remainder of this division is indeed zero)
• 43 994: indeed, 43 994 = 21997 × 2
• 65 991: indeed, 65 991 = 21997 × 3
• 87 988: indeed, 87 988 = 21997 × 4
• 109 985: indeed, 109 985 = 21997 × 5
• etc.

## Nearest numbers from 21997

Find out whether some integer is a prime number