toBits

Returns a bit representation of the specified floating-point value as Long according to the IEEE 754 floating-point "double format" bit layout.

expect fun Double.toBits(): Long(source)

fun main() {
    val value: Double = 3.1415
    val bits: Long = value.toBits()
    println("Double value: $value")
    println("Bit representation: 0x${bits.toString(16)}")
}

Source