An account number is another method, in addition to a name, to refer to one of your general ledger accounts.
These numbers can save you time by providing quick reference to your accounts. You should assign account numbers in ranges corresponding to their different types.
The standard account numbers in NetSuite are four digits, but your account numbers can be as long as 60 alphanumeric characters. NetSuite automatically updates existing records when you change an account number.
To enter or change an account number:
Go to Setup > Accounting > Manage G/L > Chart of Accounts (Administrator).
Click Edit next to the account you want to change.
On the Edit Account page, enter the number you want to use in the Number field.