Convert from arroba [Spain] to electron

Unit Definition (arroba [Spain])
The arroba [Spain] is a traditional unit of weight in Spain and Portugal, equal to 1/4 quintal. However, the Spanish and Portuguese quintals are of different sizes. In Spain, the arroba equals 25.36 pounds (11.50 kilograms); arrobas of very similar sizes were established in the Spanish speaking countries of Latin America. The arroba has also been used as a metric unit equal to exactly 15 kilograms. The name of the unit comes from ar rub', Arabic for "the quarter."

Unit Definition (electron)
The electron is the mass of the electron, often used as a unit of mass in particle physics. An electron has a mass of about 9.109 382 x 10E-31 kilogram, 9.109 382 x 10E-28 gram, or 0.510 9989 million electronvolts.