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Why 81 have an odd number of factors and 40 have an even number of factors?
A number will have an odd number of factors if and only if one of those factors is the square root of the number. This is because any factor of a number you can find must pair up with another factor of that number, and multiply to give the number. The only exception is when the factor would be paired with itself. In other words, be the square root. 81 is a square number, and so the factor 9 (square root of 81) will not pair with any other factor, meaning 81 will have an odd number of factors. 40 has an even number of factors, because it is not a square number, and so all its factors can pair up.
How many odd numbers are between 81 and 1453?
The answer is 685 odd numbers, 686 even numbers "between" 81 and 1453. If it said "to" you would include them.- 82 through 100 is 9 odd numbers and 10 evens- there are 50 (half) even/odd numbers per 100, so 100-1400 is 13 x 50 = 650 of each even/odd- there are 26 odd numbers, 26 even numbers in the remaining 52, since between doesn't include 1453.- total odd numbers is 9 + 650 + 26 = 685---The number range counting from 81 up to 1453 is 1453 - 81=1372, in which half the numbers are odd numbers or 1372/2 = 686. Since the question said "between" you would also have to exclude 1453, so the total result is 685.To test this, add twice 685 (1370) to 81 (one for each successive even then odd number) and you get 1451, the last odd number before 1453.*If you want the total of odd numbers from 1 to 1453 (including those numbers), it is 727: the number range includes 1453 numbers, 727 odd numbers and 726 even numbers. There are no half numbers.
Why do some of the factor rainbows have an even number of factors and some have an odd number of factors?
Factor rainbows display the prime factors of a given number. Some numbers, Like 27, have an odd number of prime factors. Some numbers, like 81, have an even number of prime factors.
Which numbers between 1 and 100 have an odd number of factors?
1, 4, 9, 16, 25, 36, 49, 64, 81, 100
How many integers less than 100 have an odd number of factors?
There are 9 integers less than 100 that have an odd number of factors.Every factor of a number has a pair, eg 2 & 3 are a factor pair of 6; and so it would be expected that every number has an even number of factors.However, if the factor pair of a number are the same number (eg 6 & 6 are a factor pair of 36), then there will be an odd number of factors.When there is a repeated factor like this, the number is a perfect square.Thus only perfect squares have an odd number of factors.Less than 100 there are 9 perfect squares (1, 4, 9, 16, 25, 36, 49, 64 & 81) which have an odd number of factors.100 itself is a perfect square and also has an odd number of factors, but the question asked for those numbers less than 100 with an odd number of factors.
What is the prime number of 81 is it even or odd?
81 is an odd composite number.
Is 81 a even number?
No, 81 is an odd number.
Is 81 an odd or even number?
An even number can be divided by 2 evenly. An odd number will have a remainder of 1 when divided by 2. 81 is an odd number.
Is 25 plus 56 even or odd?
25 + 56 = 81 81 = odd number
How is 81 an odd number?
An odd number is a whole number that can not be evenly divided by 2. 81 divided by 2 is 40.5 (which is not a whole number, because of the fraction of a number, .5) therefore, it is an odd number.
Is 81 an odd number?
Yes, it is.
Which number is odd 16 36 64 27 81?
27 and 81
What is the sum of the first 9 odd numbers?
The sum of the first nine odd numbers is 81.
Which is the odd number 16 36 64 27 81?
27 and 81 are the odd numbers. Since odd numbers are 1, 3, 5, 7 and 9, look at the last number and you will be able to tell if it's odd or even.
What is the sum of the first 81 odd numbers?
6,561
Is 81 in the 2 times tables?
No because it is an odd number
Is 81 a rational number?
Yes. 81 is a:- Real number - Rational number - Integer - Natural number - Counting number - Square number - Odd number
