Is 425 a prime number?

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

For 425, the answer is: No, 425 is not a prime number.

The list of all positive divisors (i.e., the list of all integers that divide 425) is as follows: 1, 5, 17, 25, 85, 425.

For 425 to be a prime number, it would have been required that 425 has only two divisors, i.e., itself and 1.

Find out more:

What is a prime number?

Actually, one can immediately see that 425 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 425 is 5, so it is divisible by 5 and is therefore not prime.

As a consequence:

425 is a multiple of 1
425 is a multiple of 5
425 is a multiple of 17
425 is a multiple of 25
425 is a multiple of 85

For 425 to be a prime number, it would have been required that 425 has only two divisors, i.e., itself and 1.

Is 425 a deficient number?

Yes, 425 is a deficient number, that is to say 425 is a natural number that is strictly larger than the sum of its proper divisors, i.e., the divisors of 425 without 425 itself (that is 1 + 5 + 17 + 25 + 85 = 133).

Parity of 425

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

Find out more:

What is an even number?

Is 425 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 425 is about 20.616.

Thus, the square root of 425 is not an integer, and therefore 425 is not a square number.

What is the square number of 425?

The square of a number (here 425) is the result of the product of this number (425) by itself (i.e., 425 × 425); the square of 425 is sometimes called "raising 425 to the power 2", or "425 squared".

The square of 425 is 180 625 because 425 × 425 = 425² = 180 625.

As a consequence, 425 is the square root of 180 625.

Number of digits of 425

425 is a number with 3 digits.

What are the multiples of 425?

The multiples of 425 are all integers evenly divisible by 425, that is all numbers such that the remainder of the division by 425 is zero. There are infinitely many multiples of 425. The smallest multiples of 425 are:

0: indeed, 0 is divisible by any natural number, and it is thus a multiple of 425 too, since 0 × 425 = 0
425: indeed, 425 is a multiple of itself, since 425 is evenly divisible by 425 (we have 425 / 425 = 1, so the remainder of this division is indeed zero)
850: indeed, 850 = 425 × 2
1 275: indeed, 1 275 = 425 × 3
1 700: indeed, 1 700 = 425 × 4
2 125: indeed, 2 125 = 425 × 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 425). 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 20.616). 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 425

Preceding numbers: …423, 424
Following numbers: 426, 427…

Nearest numbers from 425

Preceding prime number: 421
Following prime number: 431