Is 987 a prime number?

It is possible to find out using mathematical methods whether a given integer is a prime number or not.

For 987, the answer is: No, 987 is not a prime number.

The list of all positive divisors (i.e., the list of all integers that divide 987) is as follows: 1, 3, 7, 21, 47, 141, 329, 987.

For 987 to be a prime number, it would have been required that 987 has only two divisors, i.e., itself and 1.

Find out more:

What is a prime number?

As a consequence:

987 is a multiple of 1
987 is a multiple of 3
987 is a multiple of 7
987 is a multiple of 21
987 is a multiple of 47
987 is a multiple of 141
987 is a multiple of 329

For 987 to be a prime number, it would have been required that 987 has only two divisors, i.e., itself and 1.

Is 987 a deficient number?

Yes, 987 is a deficient number, that is to say 987 is a natural number that is strictly larger than the sum of its proper divisors, i.e., the divisors of 987 without 987 itself (that is 1 + 3 + 7 + 21 + 47 + 141 + 329 = 549).

Parity of 987

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

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What is an even number?

Is 987 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 987 is about 31.417.

Thus, the square root of 987 is not an integer, and therefore 987 is not a square number.

What is the square number of 987?

The square of a number (here 987) is the result of the product of this number (987) by itself (i.e., 987 × 987); the square of 987 is sometimes called "raising 987 to the power 2", or "987 squared".

The square of 987 is 974 169 because 987 × 987 = 987² = 974 169.

As a consequence, 987 is the square root of 974 169.

Number of digits of 987

987 is a number with 3 digits.

What are the multiples of 987?

The multiples of 987 are all integers evenly divisible by 987, that is all numbers such that the remainder of the division by 987 is zero. There are infinitely many multiples of 987. The smallest multiples of 987 are:

0: indeed, 0 is divisible by any natural number, and it is thus a multiple of 987 too, since 0 × 987 = 0
987: indeed, 987 is a multiple of itself, since 987 is evenly divisible by 987 (we have 987 / 987 = 1, so the remainder of this division is indeed zero)
1 974: indeed, 1 974 = 987 × 2
2 961: indeed, 2 961 = 987 × 3
3 948: indeed, 3 948 = 987 × 4
4 935: indeed, 4 935 = 987 × 5
etc.

How to determine whether an integer is a prime number?

To determine the primality of a number, several algorithms can be used. The most naive technique is to test all divisors strictly smaller to the number of which we want to determine the primality (here 987). First, we can eliminate all even numbers greater than 2 (and hence 4, 6, 8…). Then, we can stop this check when we reach the square root of the number of which we want to determine the primality (here the square root is about 31.417). Historically, the sieve of Eratosthenes (dating from the Greek mathematics) implements this technique in a relatively efficient manner.

More modern techniques include the sieve of Atkin, probabilistic algorithms, and the cyclotomic AKS test.

Numbers near 987

Preceding numbers: …985, 986
Following numbers: 988, 989…

Nearest numbers from 987

Preceding prime number: 983
Following prime number: 991