It's about 15,000 times as heavy as a Battery (D)
In other words, 2,100 kilograms is 15,600 times the weight of a Battery (D), and the weight of a Battery (D) is 0.00006410 times that amount.(Alkaline)
A "D" size battery weighs 0.1350 kilograms. The D size battery is the oldest of the modern battery sizes, first invented by the National Carbon Company in 1898.
It's about 20,000 times as heavy as a Deck of Cards
In other words, 2,100 kilograms is 22,000 times the weight of a Deck of Cards, and the weight of a Deck of Cards is 0.0000450 times that amount.(ISO 216 B8 size, a.k.a. "poker size" 63 x 88 mm, 52-card deck)
A deck of 52 ISO 216 B8-size playing cards weighs 0.094 kilograms. Utilizing nearly 3,700 decks, the record-holding largest card tower was built in early 2010, stood over 3.5 m (11 ft), and weighed over 272 kg.
It's about 30,000 times as heavy as a Battery (C)
In other words, 2,100 kilograms is 32,000 times the weight of a Battery (C), and the weight of a Battery (C) is 0.0000310 times that amount.(Alkaline)
A "C" size battery weighs 0.065 kilograms. C batteries are typically used in medium-drain devices such as musical instruments.
It's about 35,000 times as heavy as a Tennis Ball
In other words, 2,100 kilograms is 36,400 times the weight of a Tennis Ball, and the weight of a Tennis Ball is 0.00002750 times that amount.(ITF Standard; for Type 2 ball)
Per International Tennis Federation standard, regulation tennis balls must weigh about 0.0577 kilograms. Competition balls are also tested for bounce height, with the standards requiring that a ball dropped from 254 cm must bounce back to a height of 135 cm to 147 cm.
It's about 45,000 times as heavy as a Golf Ball
In other words, 2,100 kilograms is 45,720 times the weight of a Golf Ball, and the weight of a Golf Ball is 0.000021870 times that amount.(per R&A USGA Rules of Golf; maximum rule weight)
According to the Rules of Golf (as approved by the United States Golf Association and the Rules Committee of the Royal and Ancient Golf Club of Saint Andrews), golf balls must weigh no more than 0.04593 kilograms. Golf balls are not required to have the familiar dimpled pattern, but the design has been popular since its invention in 1905 because it reduces drag while increasing lift.
It's about one-fifty-five-thousandth as heavy as The CN Tower
In other words, 2,100 kilograms is 0.000017810 times the weight of The CN Tower, and the weight of The CN Tower is 56,148 times that amount.(a.k.a. La Tour CN, a.k.a. Canadian National Tower, a.k.a. Canada's National Tower) (Toronto, Canada)
The CN Tower weighs approximately 117,910,000 kilograms. The Tower is home to the world's highest glass floor — a viewing area that allows visitors to look straight down 342 m (1,120 ft) to the ground below.
It's about 60,000 times as heavy as a Light Bulb
In other words, 2,100 kilograms is 62,000 times the weight of a Light Bulb, and the weight of a Light Bulb is 0.0000160 times that amount.(a.k.a. lamp) (for A19-size, 60w, incandescent bulb by Bulbrite; package weight)
A standard, sixty-watt light bulb weighs about 0.034 kilograms. The tightly-coiled filament inside a bulb of this size would measure about 579mm if uncoiled and stretched out.