The exact factorial of 1 is:

1

📌 Number of digits in the exact factorial of 1! = 1.

Approximately, the value of 1! can also be written as 1.

How to calculate 1!

The formula for finding the factorial of a number is:

n! = n × (n-1) × (n-2) × … × 2 × 1

The same formula can also be written in terms of PI product notation as:

Factorial Formula

So, by definition, 1! is calculated as:

1

Also see:

Frequently asked questions

Here are some frequently asked questions about factorial of 1:

How many digits are there in the exact value of 1!?

There are 1 digits in the exact value of 1!.

What is the value of 1 factorial in terms of E?

The value of 1! in terms of E is 1.

What are the uses of factorials?

According to Wikipedia:

In mathematical analysis, factorials are used in power series for the exponential function and other functions, and they also have applications in algebra, number theory, probability theory, and computer science.