Step: Writing the given numerals as per International numeral system
The given numeral is written as per the Indian numeral system as it does not have a comma after every three-digit from right to left.
As per Indian system, counting from the right-hand side towards the left-hand side, we have
(1) One’s period = First three digits (906) i.e., hundreds, tens and ones.
(2) Thousand’s period = next two digits (815) i.e., ten thousand and thousands.
While reading a numeral, all the digits in the same period are read together and the name of the period (except ones) is read along with it.
Therefore, 815,906 is eight hundred fifteen thousand, nine hundred six in words.