Numbers speak more than words

Today, I am here to bring your attention to some extraordinary numbers , which look just like other numbers but carry some special attributes. And, as always, I won't bring you the solutions , you have to identify these numbers :

1, Armstrong Number:
There are some three digit numbers, which possess this characteristic. Armstrong numbers are those numbers, which equal to the sum of cubes of all its digits. There are four numbers having this characteristic. I will give you one. Find the other three.
153- here cube of 1…5…3 is 1…125…27 and sum of 1,125,27 is 153 itself. So, this number is called Armstrong number. Bring me other three. :)

2. Ramanujan Number:
First number which can be written as sum of two cubes in two different way.
You don't need much information in this criteria. Just test your brain and come up with the answer.

3. Perfect Number:
A number is called perfect, if sum of all its positive divisors excluding itself equal to that number itself. For example: 6
6 has positive divisors- 1,2,3 (and 6, which is excluded) so, its sum is 6 too. (1+2+3) Thus, 6 is perfect number.
(FUN FACT: THIS IS SO CALLED REASON WHY 6 HAS BIGGER INFLUENCE IN HISTORY.)
Get me other perfect numbers.

All the best Logic Lovers. I hope you will succeed.