calculate number of divisor with formula total div = ( p1 + 1 ) * ( p2 + 1 ) * ... . . * ( pn + 1 ) where n = ( a1 ^ p1 ) * ( a2 ^ p2 ) . ... * ( an ^ pn ) ai being prime divisor for n and pi are their respective power in factorization
$ count = 0 ; if ( $ n % $ p == 0 ) { while ( $ n % $ p == 0 ) { $ n = ( $ n / $ p ) ; $ count ++ ; } $ total = $ total * ( $ count + 1 ) ; } } } return $ total ; }