🌐EnglishEnglishEspañolFrançaisItalianoNederlandsPolskiРусскийالعربية한국어中文日本語EntityQ1149225· pop 18· linked from 51 articlesEuler's four-square identityproduct of sums of four squares is a sum of four squaresAvailable in 18 languagesEspañolFrançais中文日本語РусскийItalianoالعربيةArmenianCatalanConnectionsmathematicsEntityLeonhard EulerEntityCategoriesAlgebraic identitiesElementary number theoryLeonhard EulerQuaternionsSquares in number theory