row size too large

[kaji Pasa]

I got the error row size too large and then was trying to find the isse.
I found that the row size for mysql table id 65,535 byte

Now when i give the query
drop table if exists t;
CREATE TABLE t (a VARCHAR(4000),
b VARCHAR(4000),
c VARCHAR(4000),
d VARCHAR(4000),
e VARCHAR(4000),
f VARCHAR(4000)) ;
+i get the row size too larger, though the row size for each column is 4000 byte(or 4000+1 i.e. length + 1 byte )
For my case total size would be 6*4000+ 6 = 24006 bytes.Beacuse the error is still, i want to know if my understanding is wrong and what is the correct explanation for this error.