Half a million is written as 500,000 in number form. This is because ‘half a million’ means 500,000 units. The number 500,000 is composed of the digit 5 followed by five zeros. The comma is used as a thousand separator to make the number easier to read. For example, 500,000 is easier to read and understand than 500000. This format is commonly used in financial and statistical contexts to represent large numbers clearly.