An integer is a whole number, either positive, negative, or zero. Inside an Android device, a container capable of holding an int is called a variable of type int, and can hold any integer in the range −2,147,483,648 = −231 to 2,147,483,647 = 231 − 1 inclusive. (In the language Java, don’t write the commas.)
To hold integers outside of this range, we must use a variable of type long. But a long is more expensive than an int: it occupies twice as much memory (storage space).