What is the factorial of 400? (400!) 400 Factorial

What is the factorial of 400?

Here we will show you how to calculate the factorial of 400 (aka 400 factorial) and give you the approximate scientific notation answer and the exact answer.

Before we begin, note that the factorial of 400 can be written as 400 followed by an exclamation mark like this: 400!

Factorial of 400 means that you multiply 400 by every number below it. Therefore, you calculate the factorial of 400 by multiplying 400 by 399, then by 398, and so on all the way down to 1. In other words, we calculate 400 × 399 × 398 × ... × 1 to get 400 factorial.

The answer to 400 factorial (400!) contains 869 digits and we have listed the exact entire answer at the bottom of this page. However, below is the approximate scientific notation answer to 400 factorial:

6.4034522846 × 10⁸⁶⁸

The answer above is also sometimes written as 6.4034522846e+868. Regardless, it means that the approximate answer to 400! is 64034522846 followed by 858 more digits.

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Like we promised, below is the exact answer to 400 factorial (400!) with all 869 digits:

64034522846623895262347970319503005850702583026002959458684445942802397169186831436278478647463264676294350575035856810848298162883517435228961988646802997937341654150838162426461942352307046244325015114448670890662773914918117331955996440709549671345290477020322434911210797593280795101545372667251627877890009349763765710326350331533965349868386831339352024373788157786791506311858702618270169819740062983025308591298346162272304558339520759611505302236086810433297255194852674432232438669948422404232599805551610635942376961399231917134063858996537970147827206606320217379472010321356624613809077942304597360699567595836096158715129913822286578579549361617654480453222007825818400848436415591229454275384803558374518022675900061399560145595206127211192918105032491008000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

What is the factorial of 401?
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