1001 is the natural number preceding 1002 and following 1000.

1001
Cardinal	One thousand [and] one
Ordinal	1001st
Factorization
Roman numeral	MI
Binary	1111101001
Hexadecimal	3E9

In mathematics

One thousand one is a sphenic number and a pentagonal number.

In other fields

It is sometimes used as a generic term for "many":

1001 uses for...

1001 ways to...

In Arabic culture, this is phrased in an unusual way:

1001 Arabian Nights, in Arabic Alf layla wa layla, which literally translates as "One thousand nights and a night".

1001 thanks is Alf shukran wa shukran: "One thousand thanks and thank you".

1001 was the name of a popular British detergent in the 1960s, supposedly with "1001 uses".

In the Mawlawiyyah order of Sufi Islam, a novice must complete 1001 days of prayer before becoming a dada, or junior teacher of the faith.

In many cases, including the title Thousand and One Nights, 1001 is meant to indicate a "large number", but hardly to be taken literally.

There are countless book titles starting with 1001. About twice as many books currently in print start with 1001 as with 1000. This marketing scheme is used to imply that the customer is getting a little extra information beyond books that have only 1000 items. For example:

1001 Symbols , by Jack Tresidder

1001 Pelargoniums , by Hazel Key

1001 Perennials , by Claire Austin

1001 Things to Spot in the Sea , by Katie Daynes

1001 Animal Quacker Jokes , by Jasmine Birtles

1001 Animals to Spot , by G. Doherty

1001 Ways to Relax , by Mike George

1001 Jokes .

There are also many film titles starting with 1001. For example:

1001 Rezepte eines verliebten Kochs

1001 Nights of Pleasure

1001 Ways to Kill Yourself

Bugs Bunny's 1001 Rabbit Tales

Buckminster Fuller called 1001 (a palindromic number) a Scheherezade number in his book "Synergetics", since Scheherezade was the name of the story-telling wife in the "1001 Arabian Nights"

This article is about the number. See also the years AD 1001 and 1001 BC.