Where does 2780 come from?

In Japanese, kanji have multiple readings, on-yomi (Chinese-derived)
and kun-yomi (native Japanese). This flexibility also applies to numbers, so “2, 7, 8, 0” can be read as “fu, na, ya, ma.”

My surname is Funayama, and my family use 2780 in things

like our license plate, phone numbers, and email!

2780 has become a little family code for us ☺︎