Английская Википедия:263 (number)
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Шаблон:Infobox number 263 (two hundred [and] sixty-three) is the natural number between 262 and 264. It is also a prime number.
In mathematics
263 is a balanced prime,[1] an irregular prime,[2] a Ramanujan prime,[3] a Chen prime,[4] and a safe prime.[5]
It is also a strictly non-palindromic number and a happy number.[6]
References