Calculating the factorial of Avogadro's number (approximately 6.022 x 10^23) is impractical due to its immense size, which exceeds 6.02 x 10^23 digits. Stirling's approximation is recommended for estimating such large factorials, providing a formula that simplifies calculations. The approximation indicates that n! can be represented as e^(n(ln(n) - 1)), which is useful for understanding the scale of the number. Users have shared experiences with large factorials, noting significant computational time even for smaller values like 1,000,000!. For practical purposes, using Stirling's approximation is the most feasible approach to estimate the factorial of Avogadro's number.