How to calculate the factorial of 81
To find 81 factorial, or 81!, simply use the formula that multiplies the number 81 by all positive whole numbers less than it.
Let's look at how to calculate the Factorial of Eighty-one :
81! is exactly : 5797126020747367985879734231578109105412357244731625958745865049716390179693892056256184534249745940480000000000000000000
Factorial of 81 can be calculated as:
81! = 81 x 80 x 79 x 78 x ... x 3 x 2 x 1
The number of trailing zeros in 81! is 19
The number of digits in 81 factorial is 121.
Factorials of Numbers similar to 81
What Is Factorial?
A factorial is showed by an integer and an exclamation symbol. In arithmetic, factorial is a multiplication function of natural numbers .
It multiplies the number by every standard number that is less than it .
Symbolically, it is represented as "!".
The function is used, among other things, to get the "n" way pieces can be positioned .
To find the factorial of any given number, exchange the exact value for n in the given solution :
n! = n × (n-1) × (n-2) × (n-3) × ….× 3 × 2 × 1
The expansion of the formula shows the numbers to be replicated with each other to find the factorial of the number.
We can also figure out a factorial from the previous one. The factorial of any number is that number times the factorial of (that number minus 1).
So the rule is : n! = n × (n−1)!
81! Factorial = 81 x 80 x 79 x 78 x ... x 3 x 2 x 1 = 81 × 80! = 5797126020747367985879734231578109105412357244731625958745865049716390179693892056256184534249745940480000000000000000000
What are Factorials Used For?
The best use of factorial is in Combinations and Permutations.
Example : Determine how to arrange letters without repeating?
There one way for 1 letter "a":
2 ways for two letters "ab": ab, ba.
There are 6 ways for 3 letters "abc": abc acb cab bac bca.
There are 24 ways for 1234 of the letters "abcd"
Frequently Asked Questions on Factorial
1) Can we have factorials for negative numbers ?
Negative integer factorials are undefined
2) What Is 0!
Zero factorial or Factorial of 0 is simple, and its own value is equal to 1. So, 0! = 1.