Is 278 a prime number?

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

For 278, the answer is: No, 278 is not a prime number.

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

For 278 to be a prime number, it would have been required that 278 has only two divisors, i.e., itself and 1.

Find out more:

What is a prime number?

As a consequence:

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

For 278 to be a prime number, it would have been required that 278 has only two divisors, i.e., itself and 1.

However, 278 is a semiprime (also called biprime or 2-almost-prime), because it is the product of a two non-necessarily distinct prime numbers. Indeed, 278 = 2 x 139, where 2 and 139 are both prime numbers.

Is 278 a deficient number?

Yes, 278 is a deficient number, that is to say 278 is a natural number that is strictly larger than the sum of its proper divisors, i.e., the divisors of 278 without 278 itself (that is 1 + 2 + 139 = 142).

Parity of 278

278 is an even number, because it is evenly divisible by 2: 278 / 2 = 139.

Find out more:

What is an even number?

Is 278 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 278 is about 16.673.

Thus, the square root of 278 is not an integer, and therefore 278 is not a square number.

What is the square number of 278?

The square of a number (here 278) is the result of the product of this number (278) by itself (i.e., 278 × 278); the square of 278 is sometimes called "raising 278 to the power 2", or "278 squared".

The square of 278 is 77 284 because 278 × 278 = 278² = 77 284.

As a consequence, 278 is the square root of 77 284.

Number of digits of 278

278 is a number with 3 digits.

What are the multiples of 278?

The multiples of 278 are all integers evenly divisible by 278, that is all numbers such that the remainder of the division by 278 is zero. There are infinitely many multiples of 278. The smallest multiples of 278 are:

0: indeed, 0 is divisible by any natural number, and it is thus a multiple of 278 too, since 0 × 278 = 0
278: indeed, 278 is a multiple of itself, since 278 is evenly divisible by 278 (we have 278 / 278 = 1, so the remainder of this division is indeed zero)
556: indeed, 556 = 278 × 2
834: indeed, 834 = 278 × 3
1 112: indeed, 1 112 = 278 × 4
1 390: indeed, 1 390 = 278 × 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 278). 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 16.673). 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 278

Preceding numbers: …276, 277
Following numbers: 279, 280…

Nearest numbers from 278

Preceding prime number: 277
Following prime number: 281