Is 556 a prime number?

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

For 556, the answer is: No, 556 is not a prime number.

The list of all positive divisors (i.e., the list of all integers that divide 556) is as follows: 1, 2, 4, 139, 278, 556.

For 556 to be a prime number, it would have been required that 556 has only two divisors, i.e., itself and 1.

Find out more:

What is a prime number?

As a consequence:

556 is a multiple of 1
556 is a multiple of 2
556 is a multiple of 4
556 is a multiple of 139
556 is a multiple of 278

For 556 to be a prime number, it would have been required that 556 has only two divisors, i.e., itself and 1.

Is 556 a deficient number?

Yes, 556 is a deficient number, that is to say 556 is a natural number that is strictly larger than the sum of its proper divisors, i.e., the divisors of 556 without 556 itself (that is 1 + 2 + 4 + 139 + 278 = 424).

Parity of 556

556 is an even number, because it is evenly divisible by 2: 556 / 2 = 278.

Find out more:

What is an even number?

Is 556 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 556 is about 23.580.

Thus, the square root of 556 is not an integer, and therefore 556 is not a square number.

What is the square number of 556?

The square of a number (here 556) is the result of the product of this number (556) by itself (i.e., 556 × 556); the square of 556 is sometimes called "raising 556 to the power 2", or "556 squared".

The square of 556 is 309 136 because 556 × 556 = 556² = 309 136.

As a consequence, 556 is the square root of 309 136.

Number of digits of 556

556 is a number with 3 digits.

What are the multiples of 556?

The multiples of 556 are all integers evenly divisible by 556, that is all numbers such that the remainder of the division by 556 is zero. There are infinitely many multiples of 556. The smallest multiples of 556 are:

0: indeed, 0 is divisible by any natural number, and it is thus a multiple of 556 too, since 0 × 556 = 0
556: indeed, 556 is a multiple of itself, since 556 is evenly divisible by 556 (we have 556 / 556 = 1, so the remainder of this division is indeed zero)
1 112: indeed, 1 112 = 556 × 2
1 668: indeed, 1 668 = 556 × 3
2 224: indeed, 2 224 = 556 × 4
2 780: indeed, 2 780 = 556 × 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 556). 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 23.580). 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 556

Preceding numbers: …554, 555
Following numbers: 557, 558…

Nearest numbers from 556

Preceding prime number: 547
Following prime number: 557