It's about 60,000,000 times as heavy as a Golf Ball
In other words, 0.00273 megatonnes is 59,440,000 times the weight of a Golf Ball, and the weight of a Golf Ball is 0.000000016820 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 0.000000000045930 megatonnes. 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 45,000,000 times as heavy as a Tennis Ball
In other words, 0.00273 megatonnes is 47,300,000 times the weight of a Tennis Ball, and the weight of a Tennis Ball is 0.00000002110 times that amount.(ITF Standard; for Type 2 ball)
Per International Tennis Federation standard, regulation tennis balls must weigh about 0.00000000005770 megatonnes. 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 40,000,000 times as heavy as a Battery (C)
In other words, 0.00273 megatonnes is 42,000,000 times the weight of a Battery (C), and the weight of a Battery (C) is 0.0000000240 times that amount.(Alkaline)
A "C" size battery weighs 0.0000000000650 megatonnes. C batteries are typically used in medium-drain devices such as musical instruments.
It's about 30,000,000 times as heavy as a Deck of Cards
In other words, 0.00273 megatonnes is 29,000,000 times the weight of a Deck of Cards, and the weight of a Deck of Cards is 0.0000000340 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 0.0000000000940 megatonnes. 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 0.000000230 megatonnes.
It's about 20,000,000 times as heavy as a Battery (D)
In other words, 0.00273 megatonnes is 20,200,000 times the weight of a Battery (D), and the weight of a Battery (D) is 0.00000004950 times that amount.(Alkaline)
A "D" size battery weighs 0.0000000001350 megatonnes. The D size battery is the oldest of the modern battery sizes, first invented by the National Carbon Company in 1898.
It's about 20,000,000 times as heavy as a Baseball
In other words, 0.00273 megatonnes is 18,789,837.2921670 times the weight of a Baseball, and the weight of a Baseball is 0.0000000532202586137810 times that amount.(MLB rules)
Per Major League Baseball rules, a baseball must weigh between 0.0000000001417476156250 megatonnes and 0.000000000148834996406250 megatonnes. A major league pitcher can throw a baseball at up to 150 kph (91 mph) (with a fastball pitch), with record-setting pitches as fast as 171 kph (106 mph).
It's about 15,000,000 times as heavy as a Billiard Ball
In other words, 0.00273 megatonnes is 16,747,463.6734530 times the weight of a Billiard Ball, and the weight of a Billiard Ball is 0.0000000597105340544870 times that amount.(American-style, WPA specifications)
Per the World Pool-Billiard Association, a billiard ball weight must weigh between 0.00000000015592237718750 megatonnes and 0.000000000170097138750 megatonnes. According to legend, the difficulty in obtaining elephant ivory for the manufacture of billiard balls in the 19th century inspired the search for a replacement material, which led to the development of the first industrial plastic.