long

long is a 64-bit signed integer — reach for it when a value would overflow the 32-bit int: a 64-bit hash or content id, an accumulated playtime in milliseconds, a large score or currency total, packed bit flags. Arithmetic (+ - * / %), comparison, and the bitwise operators all work on it, and mixing an int with a long promotes the int to 64 bits automatically — so big * count where big is a long computes in 64 bits and does not overflow. print and string render all its digits.

One limit to know: a numeric *literal* is still parsed as a 32-bit int, so build large values by widening — assign a smaller literal into a long and compute from there (let m: long = 1000000 then m * m) rather than writing a 10-digit literal directly.