Is 2520 the Smallest Number Divisible by Numbers from 1 to 100?

Is 2520 the Smallest Number Divisible by Numbers from 1 to 100?

The claim that 2520 is the smallest number divisible by all the numbers from 1 to 100 is often seen but it is fundamentally incorrect. Let's delve into the mathematics behind this to understand why 2520 is not the smallest such number and what is the correct answer.

Mathematical Approach to Finding the Smallest Number Divisible by 1 to 100

Instead of 2520, to find the smallest number that can be divided exactly by all the numbers from 1 to 100, one must calculate the least common multiple (LCM) of all the numbers from 1 to 100. The LCM is determined by taking the highest power of each prime number that appears in the factorization of any of the numbers from 1 to 100. This approach ensures that no number from 1 to 100 divides the result with a remainder.

Calculating the LCM of Numbers from 1 to 100

The formula for the LCM of a set of numbers is derived from the prime factorization of each number in the set. Each prime factor must be included in the LCM with the highest power present in any of the numbers' factorizations.

For the number range from 1 to 100, the prime factorizations and their highest powers are as follows:

2: 2^6 (since 2^7 is 128, which is greater than 100) 3: 3^4 (since 3^5 is 243, which is greater than 100) 5: 5^2 (since 5^3 is 125, which is greater than 100) 7: 7^2 (since 7^3 is 343, which is greater than 100) 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97: These primes can only appear as their first power in the LCM (since they are all less than 100).

Combining these primes with their highest powers gives us the LCM of 1 to 100.

Conclusion of the LCM Calculation

The LCM of the numbers from 1 to 100 is calculated as:

2^6 * 3^4 * 5^2 * 7^2 * 11 * 13 * 17 * 19 * 23 * 29 * 31 * 37 * 41 * 43 * 47 * 53 * 59 * 61 * 67 * 71 * 73 * 79 * 83 * 89 * 97

This value is significantly larger than 2520. After performing the calculations, the smallest number that can be divided exactly by all the numbers from 1 to 100 is approximately 6,972,037,522,971,647,872.

Further Properties of 2520

While 2520 is not the smallest number that can be divided by all numbers from 1 to 100, it does have interesting properties itself. For example:

Sum of the Squares of Four Consecutive Even Numbers: The sum of the squares of 22, 24, 26, and 28 is equal to 2520. This relationship can be shown as:

2520 22^2 24^2 26^2 28^2

Since 22 * 24 * 26 * 28 100 10^2

Product of First 25 Primes Under 100 and First 9 Primes Under 25: 2520 is also equal to:

2520 2 * Sum of the first 25 prime numbers under 100 4 * Sum of the first 9 prime numbers under 25

2520 2 * 1060 4 * 100 2520

Power Concatenation: Another interesting property of 2520 is that it can be obtained by using the powers of 3:

2520 3^2 * 3^4 * 3^5 * 3^7 2457 * 63 2520

If you concatenate 2, 4, 5, and 7, the result equals 2520.

Conclusion

It is clear from the calculations and properties described that 2520 is not the smallest number divisible by the numbers from 1 to 100, but rather the smallest number divisible by the numbers from 1 to 10. Therefore, the original question was either a typo or a misunderstanding, and the correct answer to the reinterpreted question is indeed 'yes.'

Note: The calculations and properties mentioned here serve as a deeper understanding of number theory and LCM, which are crucial topics in mathematical and computational puzzles.