int(M) M refers to the maximum display width. The maximum valid display width is 255. The display width is independent of the storage size or the range of values that the type contains.
bigint
Integer data (all numbers) from -2^63 (-9223372036854775808) to 2^63-1 (9223372036854775807). The storage size is 8 bytes.
int
Integer data (all numbers) from -2^31 (-2,147,483,648) to 2^31 - 1 (2,147,483,647). The storage size is 4 bytes. The SQL-92 synonym for int is integer.
smallint
Integer data from -2^15 (-32,768) to 2^15 - 1 (32,767). The storage size is 2 bytes.
tinyint
Integer data from 0 to 255. The storage size is 1 byte.