Is 638 a prime number? What are the divisors of 638?

Parity of 638

638 is an even number, because it is evenly divisible by 2: 638 / 2 = 319.

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Is 638 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 638 is about 25.259.

Thus, the square root of 638 is not an integer, and therefore 638 is not a square number.

What is the square number of 638?

The square of a number (here 638) is the result of the product of this number (638) by itself (i.e., 638 × 638); the square of 638 is sometimes called "raising 638 to the power 2", or "638 squared".

The square of 638 is 407 044 because 638 × 638 = 6382 = 407 044.

As a consequence, 638 is the square root of 407 044.

Number of digits of 638

638 is a number with 3 digits.

What are the multiples of 638?

The multiples of 638 are all integers evenly divisible by 638, that is all numbers such that the remainder of the division by 638 is zero. There are infinitely many multiples of 638. The smallest multiples of 638 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 638). 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 25.259). 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 638

  • Preceding numbers: …636, 637
  • Following numbers: 639, 640

Nearest numbers from 638

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