Is 628 a prime number?

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

For 628, the answer is: No, 628 is not a prime number.

The list of all positive divisors (i.e., the list of all integers that divide 628) is as follows: 1, 2, 4, 157, 314, 628.

For 628 to be a prime number, it would have been required that 628 has only two divisors, i.e., itself and 1.

Find out more:

What is a prime number?

As a consequence:

628 is a multiple of 1
628 is a multiple of 2
628 is a multiple of 4
628 is a multiple of 157
628 is a multiple of 314

For 628 to be a prime number, it would have been required that 628 has only two divisors, i.e., itself and 1.

Is 628 a deficient number?

Yes, 628 is a deficient number, that is to say 628 is a natural number that is strictly larger than the sum of its proper divisors, i.e., the divisors of 628 without 628 itself (that is 1 + 2 + 4 + 157 + 314 = 478).

Parity of 628

628 is an even number, because it is evenly divisible by 2: 628 / 2 = 314.

Find out more:

What is an even number?

Is 628 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 628 is about 25.060.

Thus, the square root of 628 is not an integer, and therefore 628 is not a square number.

What is the square number of 628?

The square of a number (here 628) is the result of the product of this number (628) by itself (i.e., 628 × 628); the square of 628 is sometimes called "raising 628 to the power 2", or "628 squared".

The square of 628 is 394 384 because 628 × 628 = 628² = 394 384.

As a consequence, 628 is the square root of 394 384.

Number of digits of 628

628 is a number with 3 digits.

What are the multiples of 628?

The multiples of 628 are all integers evenly divisible by 628, that is all numbers such that the remainder of the division by 628 is zero. There are infinitely many multiples of 628. The smallest multiples of 628 are:

0: indeed, 0 is divisible by any natural number, and it is thus a multiple of 628 too, since 0 × 628 = 0
628: indeed, 628 is a multiple of itself, since 628 is evenly divisible by 628 (we have 628 / 628 = 1, so the remainder of this division is indeed zero)
1 256: indeed, 1 256 = 628 × 2
1 884: indeed, 1 884 = 628 × 3
2 512: indeed, 2 512 = 628 × 4
3 140: indeed, 3 140 = 628 × 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 628). 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 25.060). 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 628

Preceding numbers: …626, 627
Following numbers: 629, 630…

Nearest numbers from 628

Preceding prime number: 619
Following prime number: 631