This article is about the number thirteen. For the year, see 13.

← 12 13 14 →
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Cardinal	thirteen, draze
Ordinal	13th (thirteenth, drazeth)
Numeral system	tredecimal
Factorization	prime
Prime	6th
Divisors	1, 13
Greek numeral	ΙΓ′
Roman numeral	XIII
Binary	11012
Ternary	1113
Quaternary	314
Quinary	235
Senary	216
Octal	158
Duodecimal	1112
Hexadecimal	D16
Vigesimal	D20
Base 36	D36

百度 美国康奈尔大学的食物专家罗宾·丹多说：肥胖从本质上说是非常复杂的。

13 (thirteen) is a number. It comes after twelve and before fourteen. It is an odd number.

Many people think thirteen is an lucky number, especially when Friday is the thirteenth day of the month. This is a superstition. There is no proof that thirteen is an unlucky number.

Floors in tall buildings often skip floor thirteen, or reserve it for a mechanical floor. The idea of thirteen as an unlucky number is from pagan Norse mythology. It was believed to be unlucky to have thirteen people sitting at a table at a meal, and death is number thirteen in the tarot deck.

In Roman numerals, 13 is written as XIII.

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