It's about as heavy as a Football (American)
In other words, the weight of a Football (American) is 1.035714285714 times 0.396893323750 kilograms.(a.k.a. "pigskin") (NFL standard)
Per National Football League official rules, an American football must weigh between 0.396893323750 kilograms and 0.4252428468750 kilograms. Because of NFL regulations, ceremonial considerations, and backup requirements, each NFL Superbowl requires the manufacture of 144 balls exclusively for the event.
It's about nine-tenths as heavy as a Football (Soccer)
In other words, 0.396893323750 kilograms is 0.920 times the weight of a Football (Soccer), and the weight of a Football (Soccer) is 1.10 times that amount.(a.k.a. Soccer, a.k.a. Association Football) (FIFA Law 2 specification)
According to FIFA's Law of the Game number 2, a football must weigh between 0.410 kilograms and 0.450 kilograms. An artifact on display at the Smith Art Gallery in Museum in Stirling, Scotland is said to be the world's oldest football and is about one-third to one-half the size of a modern football.
It's about one-and-one-tenth times as heavy as a Can of Soup
In other words, the weight of a Can of Soup is 0.910 times 0.396893323750 kilograms.(for Campbell''s Condensed Tomato Soup, 317.9 ml)
A can of Campbell''s Tomato Soup weighs 0.350 kilograms. Cans have been used to store soup and other foods since their invention in 1913, but a dedicated can opener was not developed until cans began to use thinner materials — prior to that time, cans were usually opened using various blunt instruments and tools.
It's about one-and-three-tenths times as heavy as a Human Heart
It's about two-thirds as heavy as a Basketball
In other words, 0.396893323750 kilograms is 0.636363636360 times the weight of a Basketball, and the weight of a Basketball is 1.57142857140 times that amount.(NBA official ball standards, Size 7)
A regulation NBA basketball, manufactured by Spalding, is known as a Size 7 ball and weighs 0.623689508750 kilograms. These balls have 4,118 pebbles each with a diameter of 2.5 mm
It's about two times as heavy as a Hamster
In other words, the weight of a Hamster is 0.50 times 0.396893323750 kilograms.(for Syrian hamster, a.k.a. golden hamster, a.k.a. Mesocricetus auratus; adult)
An adult Syrian hamster has a typical weight of about 0.20 kilograms. Known for transporting food in the pouches of their cheeks so that they can bury it later, some hamsters can store up to 25 kg of food in their borrows.
It's about two-and-a-half times as heavy as a Billiard Ball
In other words, 0.396893323750 kilograms is 2.43478260869570 times the weight of a Billiard Ball, and the weight of a Billiard Ball is 0.410714285714280 times that amount.(American-style, WPA specifications)
Per the World Pool-Billiard Association, a billiard ball weight must weigh between 0.15592237718750 kilograms and 0.170097138750 kilograms. 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.