Divisors

What is the smallest positive integer that is not a divisor of 5040?

Note: 7 ! = 5040 7! = 5040

9 11 10 12 8 13

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

4 solutions

Kay Xspre
Nov 9, 2015

As 5040 = 2 4 × 3 2 × 5 × 7 5040 = 2^4\times3^2\times5\times7 , you can observe that 2 , 4 , 8 2, 4, 8 is in 2 4 2^4 , 6 is a result of 2 × 3 2\times3 , and 5 , 7 , 9 5, 7, 9 has the respective factor. This means 1 to 9 is all factor to 5040, and 10 is also included as 10 = 2 × 5 10 = 2\times 5 . The smallest positive which is not a factor is then be 11, 13, 17 and so forth...

The divisors of 5040 are 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12 , 14, 15, 16, 18, 20, 21, 24, 28, 30, 35, 36, 40, 42, 45, 48, 56, 60, 63, 70, 72, 80, 84, 90, 105, 112, 120, 126, 140, 144, 168, 180...... and there is no 11

Gary Aknin
Nov 15, 2015

By the fundamental theorem of arithmetic, we know every integer greater than 1 either is prime itself or is the product of prime numbers, and that this product is unique, up to the order of the factors. Thus, the smallest integer that does not divides evenly into 5040 will be a prime number. The unique prime factors of 5040 = 2^4 * 3^2 * 5 * 7. The list of the first prime numbers are 2, 3, 5, 7, and 11... Thus the smallest integer is 11, which does not evenly divide into 5040.

Snehil Kumar
Nov 15, 2015

7! =2^4×3^2×5×7. so we have 8,9,10 also the divisors but 11 is a prime no. and can't be generated by these numbers.

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...