720 (number)

Seven hundred twenty is the natural number following 719 and preceding 721.

It is 6! (6 factorial), a composite number with thirty divisors, more than any number below, making it a highly composite number. It is a Harshad number in every base from binary to decimal.

720 is expressible as the product of consecutive integers in two different ways: 720 = 1 × 2 × 3 × 4 × 5 × 6 , and 720 = 8 × 9 × 10 . ^[1]

There are 49 solutions to the equation φ(x) = 720, more than any integer below it, making 720 a highly totient number.

720 is a 241-gonal number.

In other fields

720 is

• A common vertical display resolution for HDTV (see 720i and 720p).
• 720 and above is a good credit score.
• 720° is two full rotations; the term "720" is a skateboarding trick.
• 720° is also the name of a skateboarding video game.
• 720 is a dual area code in the Denver Metro Area along with 303.
• 720° is the sum of all the defects, of any polyhedron.
• 720 is a short form of saying Boeing 720, an airliner that's no longer in service.

For the year AD, see 720.

References

1. ↑ Wells, David (1987). The Penguin Dictionary of Curious and Interesting Numbers. London: Penguin Books. p. 719.