Is 640 a prime number? What are the divisors of 640?

Parity of 640

640 is an even number, because it is evenly divisible by 2: 640 / 2 = 320.

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Is 640 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 640 is about 25.298.

Thus, the square root of 640 is not an integer, and therefore 640 is not a square number.

What is the square number of 640?

The square of a number (here 640) is the result of the product of this number (640) by itself (i.e., 640 × 640); the square of 640 is sometimes called "raising 640 to the power 2", or "640 squared".

The square of 640 is 409 600 because 640 × 640 = 6402 = 409 600.

As a consequence, 640 is the square root of 409 600.

Number of digits of 640

640 is a number with 3 digits.

What are the multiples of 640?

The multiples of 640 are all integers evenly divisible by 640, that is all numbers such that the remainder of the division by 640 is zero. There are infinitely many multiples of 640. The smallest multiples of 640 are:

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 640). 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 25.298). 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 640

  • Preceding numbers: …638, 639
  • Following numbers: 641, 642

Nearest numbers from 640

  • Preceding prime number: 631
  • Following prime number: 641
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