add commas or point every 3 digits using kotlin

System.out.println(NumberFormat.getNumberInstance(Locale.US).format(35634646));

If you are on the JVM you can use

"%,d".format(input)

which gives 11,000 for input 11000. Replace , with any delimiter you require.

If you want to use predefined number formats, e.g. for the current locale, use:

java.text.NumberFormat.getIntegerInstance().format(input);

Be also sure to check the other format instances, e.g. getCurrencyInstance or getPercentInstance. Note that you can use NumberFormat also with other locales. Just pass them to the get*Instance-method.

Some of the second variant can also be found here: Converting Integer to String with comma for thousands

If you are using it via Javascript you may be interested in: How do I format numbers using JavaScript?