Largest number divisible by its digits

func largest_number(base) {

    var digits = @(base ^.. 1)

    digits.each {|k|
        digits.variations(k, {|*a|
            var n = Number(a.join, base)
            if (a.all {|d| d.divides(n) }) {
                return n
            }
        })
    }
}

say largest_number(10)   #=> 9867312