廿 廿 nian4
twenty (20), in a limited number of set expressions; also written using banker's character 念

strokes 4
radical
strokes after radical 1
廿八躔 廿八躔 nian4 ba1 chan2
the twenty-eight constellations; also written 二十八宿

廿四史 廿四史 nian4 si4 shi3
twenty four dynastic histories (or 25 or 26 in modern editions); same as 二十四史