What is a 18-digit number?

A 18-digit number is a number that has 18 digits where the first digit must be 1 or greater. On this page, we will answer three questions for you: What is the smallest 18-digit number? What is the largest 18-digit number? How many 18-digit numbers are there?

Smallest 18-digit number
The smallest 18-digit number is 1 followed by 17 zeros. This number is called one hundred quadrillion.

Largest 18-digit number
The largest 18-digit number is 9 followed by another 17 nines. This number is called nine hundred ninety-nine quadrillion nine hundred ninety-nine trillion nine hundred ninety-nine billion nine hundred ninety-nine million nine hundred ninety-nine thousand nine hundred ninety-nine.

Total number of 18-digit numbers
There are a total of nine hundred quadrillion different 18-digit numbers. nine hundred quadrillion is 9 followed by 17 zeros.

Digit Numbers
Here you can learn about another digit number.

What is a 19-digit number?
Go here for information about the next digit number on our list that we have information about.