Is 158 a prime number?

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

For 158, the answer is: No, 158 is not a prime number.

The list of all positive divisors (i.e., the list of all integers that divide 158) is as follows: 1, 2, 79, 158.

For 158 to be a prime number, it would have been required that 158 has only two divisors, i.e., itself and 1.

Find out more:

What is a prime number?

As a consequence:

158 is a multiple of 1
158 is a multiple of 2
158 is a multiple of 79

For 158 to be a prime number, it would have been required that 158 has only two divisors, i.e., itself and 1.

However, 158 is a semiprime (also called biprime or 2-almost-prime), because it is the product of a two non-necessarily distinct prime numbers. Indeed, 158 = 2 x 79, where 2 and 79 are both prime numbers.

Is 158 a deficient number?

Yes, 158 is a deficient number, that is to say 158 is a natural number that is strictly larger than the sum of its proper divisors, i.e., the divisors of 158 without 158 itself (that is 1 + 2 + 79 = 82).

Parity of 158

158 is an even number, because it is evenly divisible by 2: 158 / 2 = 79.

Find out more:

What is an even number?

Is 158 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 158 is about 12.570.

Thus, the square root of 158 is not an integer, and therefore 158 is not a square number.

What is the square number of 158?

The square of a number (here 158) is the result of the product of this number (158) by itself (i.e., 158 × 158); the square of 158 is sometimes called "raising 158 to the power 2", or "158 squared".

The square of 158 is 24 964 because 158 × 158 = 158² = 24 964.

As a consequence, 158 is the square root of 24 964.

Number of digits of 158

158 is a number with 3 digits.

What are the multiples of 158?

The multiples of 158 are all integers evenly divisible by 158, that is all numbers such that the remainder of the division by 158 is zero. There are infinitely many multiples of 158. The smallest multiples of 158 are:

0: indeed, 0 is divisible by any natural number, and it is thus a multiple of 158 too, since 0 × 158 = 0
158: indeed, 158 is a multiple of itself, since 158 is evenly divisible by 158 (we have 158 / 158 = 1, so the remainder of this division is indeed zero)
316: indeed, 316 = 158 × 2
474: indeed, 474 = 158 × 3
632: indeed, 632 = 158 × 4
790: indeed, 790 = 158 × 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 158). 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 12.570). 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 158

Preceding numbers: …156, 157
Following numbers: 159, 160…

Nearest numbers from 158

Preceding prime number: 157
Following prime number: 163