Answer:
Seven hundred and twenty-three thousand seven hundred and fifty-one.
Step-by-step explanation:
The international numeration system is a generally (world wide) acceptable means of writing or expressing the place values of digits in a given number. It give the understanding of the place value of each digit of a given number.
Example: given a number 271800, it can be written in the international system as; two hundred and seventy-one thousand eight hundred.
So that the given number can be expressed as;
723,751 = Seven hundred and twenty-three thousand seven hundred and fifty-one.