Is 511 a prime number?

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

For 511, the answer is: No, 511 is not a prime number.

The list of all positive divisors (i.e., the list of all integers that divide 511) is as follows: 1, 7, 73, 511.

For 511 to be a prime number, it would have been required that 511 has only two divisors, i.e., itself and 1.

Find out more:

What is a prime number?

As a consequence:

511 is a multiple of 1
511 is a multiple of 7
511 is a multiple of 73

For 511 to be a prime number, it would have been required that 511 has only two divisors, i.e., itself and 1.

However, 511 is a semiprime (also called biprime or 2-almost-prime), because it is the product of a two non-necessarily distinct prime numbers. Indeed, 511 = 7 x 73, where 7 and 73 are both prime numbers.

Is 511 a deficient number?

Yes, 511 is a deficient number, that is to say 511 is a natural number that is strictly larger than the sum of its proper divisors, i.e., the divisors of 511 without 511 itself (that is 1 + 7 + 73 = 81).

Parity of 511

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

Find out more:

What is an even number?

Is 511 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 511 is about 22.605.

Thus, the square root of 511 is not an integer, and therefore 511 is not a square number.

What is the square number of 511?

The square of a number (here 511) is the result of the product of this number (511) by itself (i.e., 511 × 511); the square of 511 is sometimes called "raising 511 to the power 2", or "511 squared".

The square of 511 is 261 121 because 511 × 511 = 511² = 261 121.

As a consequence, 511 is the square root of 261 121.

Number of digits of 511

511 is a number with 3 digits.

What are the multiples of 511?

The multiples of 511 are all integers evenly divisible by 511, that is all numbers such that the remainder of the division by 511 is zero. There are infinitely many multiples of 511. The smallest multiples of 511 are:

0: indeed, 0 is divisible by any natural number, and it is thus a multiple of 511 too, since 0 × 511 = 0
511: indeed, 511 is a multiple of itself, since 511 is evenly divisible by 511 (we have 511 / 511 = 1, so the remainder of this division is indeed zero)
1 022: indeed, 1 022 = 511 × 2
1 533: indeed, 1 533 = 511 × 3
2 044: indeed, 2 044 = 511 × 4
2 555: indeed, 2 555 = 511 × 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 511). 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 22.605). 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 511

Preceding numbers: …509, 510
Following numbers: 512, 513…

Nearest numbers from 511

Preceding prime number: 509
Following prime number: 521