Is 235 a prime number?

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

For 235, the answer is: No, 235 is not a prime number.

The list of all positive divisors (i.e., the list of all integers that divide 235) is as follows: 1, 5, 47, 235.

For 235 to be a prime number, it would have been required that 235 has only two divisors, i.e., itself and 1.

Find out more:

What is a prime number?

Actually, one can immediately see that 235 cannot be prime, because 5 is one of its divisors: indeed, a number ending with 0 or 5 has necessarily 5 among its divisors. The last digit of 235 is 5, so it is divisible by 5 and is therefore not prime.

As a consequence:

235 is a multiple of 1
235 is a multiple of 5
235 is a multiple of 47

For 235 to be a prime number, it would have been required that 235 has only two divisors, i.e., itself and 1.

However, 235 is a semiprime (also called biprime or 2-almost-prime), because it is the product of a two non-necessarily distinct prime numbers. Indeed, 235 = 5 x 47, where 5 and 47 are both prime numbers.

Is 235 a deficient number?

Yes, 235 is a deficient number, that is to say 235 is a natural number that is strictly larger than the sum of its proper divisors, i.e., the divisors of 235 without 235 itself (that is 1 + 5 + 47 = 53).

Parity of 235

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

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What is an even number?

Is 235 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 235 is about 15.330.

Thus, the square root of 235 is not an integer, and therefore 235 is not a square number.

What is the square number of 235?

The square of a number (here 235) is the result of the product of this number (235) by itself (i.e., 235 × 235); the square of 235 is sometimes called "raising 235 to the power 2", or "235 squared".

The square of 235 is 55 225 because 235 × 235 = 235² = 55 225.

As a consequence, 235 is the square root of 55 225.

Number of digits of 235

235 is a number with 3 digits.

What are the multiples of 235?

The multiples of 235 are all integers evenly divisible by 235, that is all numbers such that the remainder of the division by 235 is zero. There are infinitely many multiples of 235. The smallest multiples of 235 are:

0: indeed, 0 is divisible by any natural number, and it is thus a multiple of 235 too, since 0 × 235 = 0
235: indeed, 235 is a multiple of itself, since 235 is evenly divisible by 235 (we have 235 / 235 = 1, so the remainder of this division is indeed zero)
470: indeed, 470 = 235 × 2
705: indeed, 705 = 235 × 3
940: indeed, 940 = 235 × 4
1 175: indeed, 1 175 = 235 × 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 235). 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 15.330). 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 235

Preceding numbers: …233, 234
Following numbers: 236, 237…

Nearest numbers from 235

Preceding prime number: 233
Following prime number: 239