$21!=21\cdot 20!=21\cdot 243290200817664000021!=21\backslash cdot20!=21\backslash ;\backslash cdot\backslash ;2\backslash ,432\backslash ,902\backslash ,008\backslash ,176\backslash ,640\backslash ,000$ $=51090942171709440000=51\backslash ,090\backslash ,942\backslash ,171\backslash ,709\backslash ,440\backslash ,000$

In Worten:einundfünfzig Trillionen neunzig Billiarden neunhundertzweiundvierzig Billionen hunderteinundsiebzig Milliarden siebenhundertneun Millionen vierhundertvierzig Tausend