It's about 90,000 times as heavy as a Battery (AA)
In other words, 2,100 kilograms is 88,000 times the weight of a Battery (AA), and the weight of a Battery (AA) is 0.0000110 times that amount.(Alkaline)
An "AA" size battery weighs 0.024 kilograms. AA batteries came into common use during World War II and were given their name by the American National Standards Institute (ANSI) Committee C18 because they were smaller than the "A" size batteries which were invented first.
It's about one-ninety-five-thousandth as heavy as The Sears Tower
In other words, 2,100 kilograms is 0.000010410 times the weight of The Sears Tower, and the weight of The Sears Tower is 96,060 times that amount.(officially "Willis Tower" as of 2009) (Chicago, Illinois)
The Willis Tower weighs approximately 201,800,000 kilograms. The outer wall surface of the Tower is covered with black anodized aluminum panels which would total 110,000 sq. m (28 acres) if laid out together.
It's about 100,000 times as heavy as a Mouse
In other words, the weight of a Mouse is 0.00001000 times 2,100 kilograms.(a.k.a. "House mouse", Mus musculus) (adult)
The weight of a mouse is typically an average of 0.021 kilograms. While most mice typically live two to three years, the Methuselah Mouse Prize — an award administered by a non-profit organization which advances aging-related research — was once awarded to a team of scientists whose research resulted in a mouse living just under five years.
It's about 150,000 times as heavy as a Compact disc
It's about one-one-hundred-fifty-thousandth as heavy as The Empire State Building
In other words, 2,100 kilograms is 0.000006340 times the weight of The Empire State Building, and the weight of The Empire State Building is 158,000 times that amount.(New York City, New York)
The Empire State Building weighs approximately 331,000,000 kilograms. About 4% of the building's weight is its 6,000 cu. m (200,000 cu. ft) of limestone façade.
It's about 200,000 times as heavy as a Battery (AAA)
In other words, 2,100 kilograms is 180,000 times the weight of a Battery (AAA), and the weight of a Battery (AAA) is 0.00000560 times that amount.(Alkaline)
An "AAA" size battery weighs 0.012 kilograms. Batteries are named by the American National Standards Institute (ANSI) Committee C18 and AAA batteries were given their name because they were smaller than the "AA" and "A" size batteries which were invented first.
It's about 300,000 times as heavy as an Eye (Human)
In other words, the weight of an Eye (Human) is 0.00000330 times 2,100 kilograms.(adult)
A fully developed eye (in a person over the age of thirteen), weighs about 0.0071 kilograms. The pupil of the eye varies depending on the amount of light it is exposed to, but typically measures about 4 mm across.