Is 745 a prime number?

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

For 745, the answer is: No, 745 is not a prime number.

The list of all positive divisors (i.e., the list of all integers that divide 745) is as follows: 1, 5, 149, 745.

For 745 to be a prime number, it would have been required that 745 has only two divisors, i.e., itself and 1.

Find out more:

What is a prime number?

Actually, one can immediately see that 745 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 745 is 5, so it is divisible by 5 and is therefore not prime.

As a consequence:

745 is a multiple of 1
745 is a multiple of 5
745 is a multiple of 149

For 745 to be a prime number, it would have been required that 745 has only two divisors, i.e., itself and 1.

However, 745 is a semiprime (also called biprime or 2-almost-prime), because it is the product of a two non-necessarily distinct prime numbers. Indeed, 745 = 5 x 149, where 5 and 149 are both prime numbers.

Is 745 a deficient number?

Yes, 745 is a deficient number, that is to say 745 is a natural number that is strictly larger than the sum of its proper divisors, i.e., the divisors of 745 without 745 itself (that is 1 + 5 + 149 = 155).

Parity of 745

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

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What is an even number?

Is 745 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 745 is about 27.295.

Thus, the square root of 745 is not an integer, and therefore 745 is not a square number.

What is the square number of 745?

The square of a number (here 745) is the result of the product of this number (745) by itself (i.e., 745 × 745); the square of 745 is sometimes called "raising 745 to the power 2", or "745 squared".

The square of 745 is 555 025 because 745 × 745 = 745² = 555 025.

As a consequence, 745 is the square root of 555 025.

Number of digits of 745

745 is a number with 3 digits.

What are the multiples of 745?

The multiples of 745 are all integers evenly divisible by 745, that is all numbers such that the remainder of the division by 745 is zero. There are infinitely many multiples of 745. The smallest multiples of 745 are:

0: indeed, 0 is divisible by any natural number, and it is thus a multiple of 745 too, since 0 × 745 = 0
745: indeed, 745 is a multiple of itself, since 745 is evenly divisible by 745 (we have 745 / 745 = 1, so the remainder of this division is indeed zero)
1 490: indeed, 1 490 = 745 × 2
2 235: indeed, 2 235 = 745 × 3
2 980: indeed, 2 980 = 745 × 4
3 725: indeed, 3 725 = 745 × 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 745). 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 27.295). 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 745

Preceding numbers: …743, 744
Following numbers: 746, 747…

Nearest numbers from 745

Preceding prime number: 743
Following prime number: 751