Is 87 a prime number? What are the divisors of 87?

Parity of 87

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

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Is 87 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 87 is about 9.327.

Thus, the square root of 87 is not an integer, and therefore 87 is not a square number.

What is the square number of 87?

The square of a number (here 87) is the result of the product of this number (87) by itself (i.e., 87 × 87); the square of 87 is sometimes called "raising 87 to the power 2", or "87 squared".

The square of 87 is 7 569 because 87 × 87 = 872 = 7 569.

As a consequence, 87 is the square root of 7 569.

Number of digits of 87

87 is a number with 2 digits.

What are the multiples of 87?

The multiples of 87 are all integers evenly divisible by 87, that is all numbers such that the remainder of the division by 87 is zero. There are infinitely many multiples of 87. The smallest multiples of 87 are:

  • 0: indeed, 0 is divisible by any natural number, and it is thus a multiple of 87 too, since 0 × 87 = 0
  • 87: indeed, 87 is a multiple of itself, since 87 is evenly divisible by 87 (we have 87 / 87 = 1, so the remainder of this division is indeed zero)
  • 174: indeed, 174 = 87 × 2
  • 261: indeed, 261 = 87 × 3
  • 348: indeed, 348 = 87 × 4
  • 435: indeed, 435 = 87 × 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 87). 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 9.327). 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 87

  • Preceding numbers: …85, 86
  • Following numbers: 88, 89…

Nearest numbers from 87

  • Preceding prime number: 83
  • Following prime number: 89
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