Next number in the series 1, 11, 21, 1211

Next number is : 312211, Now can you guess the next number?
Check your answer:-

Tried enough already?

Here we need to count the number of individual digits, how many 1’s, how many 2’s etc.
for example
1 => one 1 => 11
11 => two 1 => 21
21 => one 2 one 1 => 1211
Thus to get 5th number in the series
111221 => three 1 two 2 one 1 => 312211
And to get the sixth number in the series
312211 => one 3 one 1 two 2 two 1=> 13112221