# A problem from my book

Number Theory Level pending

Function $$f(n)$$ is defined as the sum of digits of $$n$$ being repeated until that sum becomes a single digit. For example, [f(123456)=(1+2+3+4+5+6)=(21)=(2+1)=(3)=3.

Find the value of $$F(2612000!)$$.

Notation:
$$!$$ denotes the factorial notation. For example, $$10! = 1\times2\times3\times\cdots\times10$$.

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