1521 thousandths is equivalent to dividing the number by 1000 or by multiplying by 0.001, and in this case you get . Thousandth is a decimal number, usually used to describe a proportion or fraction of something.
Fractions are used to define distance, time, weight, et cetera.
1521 thousandths describes the fraction of something after dividing the number by a thousand. It can also be described as a fraction of a number divided by 1000.
What is 1521 thousands?
1521 thousands = 1521/1000