2520 (two thousand five hundred [and] twenty) is the natural number following 2519 and preceding 2521.

2520 is:

• the smallest number divisible by all integers from one to ten, i.e., it is their least common multiple.
• half of 7! (5040), meaning 7 factorial, or ${\displaystyle 1\times 2\times 3\times 4\times 5\times 6\times 7}$.
• the product of five consecutive numbers, namely ${\displaystyle 3\times 4\times 5\times 6\times 7}$.
• a superior highly composite number.
• a colossally abundant number.
• the last highly composite number that is half of the next highly composite number.^[1]
• the last highly composite number that is a divisor of all following highly composite numbers.^[2]
• palindromic in undecimal (1991₁₁) and a repdigit in bases 55, 59, and 62.
• a Harshad number in all bases between binary and hexadecimal.
• the aliquot sum of 1080.
• part of the 53-aliquot tree. The complete aliquot sequence starting at 1080 is 1080, 2520, 6840, 16560, 41472, 82311, 27441, 12209, 451, 53, 1, 0.