Integer and long integer literals are described by the following lexical definitions:
Although both lower case "l" and upper case "L" are allowed as suffix for long integers, it is strongly recommended to always use "L", since the letter "l" looks too much like the digit "1".
Plain integer literals that are above the largest representable plain integer (e.g., 2147483647 when using 32-bit arithmetic) are accepted as if they were long integers instead.2.1 There is no limit for long integer literals apart from what can be stored in available memory.
Some examples of plain integer literals (first row) and long integer literals (second and third rows):
7 2147483647 0177 3L 79228162514264337593543950336L 0377L 0x100000000L 79228162514264337593543950336 0xdeadbeef