What is the factorial of 100 in voice?

Attempting to read 100! fully in voice would take several minutes and is rarely done except in programming exercises or math competitions.

In short, for practical purposes, scientific notation or approximation is used when referring to factorials of large numbers like 100!.

The factorial of 100 (100!) is an extremely large number with 158 digits. In voice form, it would be read as a very long sequence of numbers, and practically nobody reads it digit by digit.

Instead of reading all digits, people often express it in scientific notation: 100! ≈ 9.332621544 × 10¹⁵⁷. In voice, you could say "nine point three three times ten to the power of one fifty seven."