What is the last number in the world

There is no "last number" in mathematics—numbers continue infinitely without end. For any number you can name, no matter how large, you can always add 1 to create an even larger number. This is a fundamental principle: the set of integers (and real numbers) extends infinitely in both positive and negative directions.

While we have names for extremely large numbers—googol (10^100), googolplex (10^googol), Graham's number, or numbers generated through arrow notation—none of these are "last" numbers. They're simply particular large numbers that can still be increased. You can always construct larger numbers through addition, multiplication, exponentiation, or more exotic operations. In practical terms, certain contexts might have "largest" values: the largest known prime number (continuously being discovered and increasing), the largest number of particles in the observable universe (approximately 10^80), or the largest number practically computable. But mathematically, the concept of a "last number" contradicts the nature of infinity itself. Numbers extend endlessly, and this infinitude is central to mathematics.