toString

Returns a string representation of the object. Can be called with a null receiver, in which case it returns the string "null".

expect fun Any?.toString(): String(source)

fun main() {
    val nullableValue: Any? = null
    println(nullableValue.toString()) // Prints: null

    val nonNullValue: Any? = "Kotlin"
    println(nonNullValue.toString()) // Prints: Kotlin
}

Source