Get type of a variable in Kotlin

You can use the is operator to check whether an object is of a specific type:

val number = 5
if(number is Int) {
   println("number is of type Int")
}

You can also get the type as String using reflection:

println(Int::class.simpleName)    // "Int"
println(Int::class.qualifiedName) // "kotlin.Int"

Please note:

On the Java platform, the runtime component required for using the
reflection features is distributed as a separate JAR file
(kotlin-reflect.jar). This is done to reduce the required size of the
runtime library for applications that do not use reflection features.
If you do use reflection, please make sure that the .jar file is added
to the classpath of your project.

Source: https://kotlinlang.org/docs/reference/reflection.html#bound-class-references-since-11