In Kotlin, everything is an object in the sense that we can call member functions and properties on any variable. Some of the types can have a special internal representation – for example, numbers, characters and booleans can be represented as primitive values at runtime – but to the user they look like ordinary classes. In this section we describe the basic types used in Kotlin: numbers, characters, booleans, arrays, and strings.

Structural Equality (‘==’)
== operator is used to compare the data of two variables.
Please don’t misunderstand this equality operator with the Java == operator as both are different. == operator in Kotlin only compares the data or variables, whereas in Java or other languages == is generally used to compare the references. The negated counterpart of == in Kotlin is != which is used to compare if both the values are not equal to each other.

Referential equality (‘===’)
=== operator is used to compare the reference of two variable or object. It will only be true if both the objects or variables pointing to the same object. The negated counterpart of === in Kotlin is !== which is used to compare if both the values are not equal to each other. For values which are represented as primitive types at runtime (for example, Int), the === equality check is equivalent to the == check.

.equals method
equals(other: Any?) method is implemented in Any class and can be overridden in any extending class. .equals method also compares the content of the variables or objects just like == operator but it behaves differently in case of Float and Double comparison.
The difference between == and .equals is in case of Float and Double comparison, .equals disagrees with the IEEE 754 Standard for Floating-Point Arithmetic.

Data type is the type of value that we will store in a variable.As an example String, Integer, Boolean etc. This data type defines the operation to be performed on the data, the purpose of the data and the value of the type can be stored. There are several kind of data type.