5 08.11

private infix fun Boolean.arrow(other: Boolean) = !(this && !other)

fun main() = generateSequence(1) { it + 1 }.first { len ->
    (1..9).map { "$it".repeat(len) }
        .firstOrNull { x ->
            (x.fold(1L) { acc, c -> acc * c.toString().toInt() }
                .toString(2) + "00")
                .toBigInteger(2).toString() == "864"
        }
        ?.let {
            println(it)
            true
        } ?: false
}.let { }