720 (number)

	List of numbers — Integers ← 0 100 200 300 400 500 600 700 800 900 →
Cardinal	seven hundred twenty
Ordinal	720th; (seven hundred twentieth)
Factorization	24× 32× 5
Divisors	1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 16, 18, 20, 24, 30, 36, 40, 45, 48, 60, 72, 80, 90, 120, 144, 180, 240, 360, 720
Greek numeral	ΨΚ´
Roman numeral	DCCXX
Binary	10110100002
Ternary	2222003
Quaternary	231004
Quinary	103405
Senary	32006
Octal	13208
Duodecimal	50012
Hexadecimal	2D016
Vigesimal	1G020
Base 36	K036

720 (seven hundred [and] 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: $720 = 1 \times 2 \times 3 \times 4 \times 5 \times 6$ , and $720 = 8 \times 9 \times 10$ . ^[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° is two full rotations; the term "720" refers to 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 which is no longer in service.

For the year AD, see 720.

References

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

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