2520 (number) is:

1-The smallest number divisible by all integers from 1 to 10, i.e. it is their least common multiple.

2-The product of five consecutive numbers, namely 3×4×5×6×7.

3-The last highly composite number which is half of the next highly composite number (5040).The highly composite number is any positive integer which has at least as many divisors as any smaller positive integer.

4-The last highly composite number that is a divisor of all following highly composite numbers.

5-It is multiplied by the numbers:7×30×12, which represents the number of days of the week, the number of days of the month (as-suming that the month is usually 30 days), and the months of the year.

More Info: en.m.wikipedia.org