16801

16801 is a number that appears in various contexts across mathematics, computing, and popular culture, often due to its unique properties and appearances in notable systems. One of its most well-known associations is with the **IBM System/360** mainframe computer series, where it was used as a reference code for certain internal operations or error messages. The number also holds significance in the **IBM 1401** and other early computing systems, where it was sometimes referenced in technical documentation or troubleshooting guides.

In mathematics, 16801 is notable as a **perfect square**, specifically the square of 130 (130² = 16801). It is also a **Harshad number**, meaning it is divisible by the sum of its digits (1 + 6 + 8 + 0 + 1 = 16, and 16801 ÷ 16 = 1050.0625, though this property is less commonly emphasized). Additionally, it appears in the context of **factorials** as part of the expansion of (1 + x)^n, where its coefficient in the binomial expansion of (1 + x)^130 is 1.

In computing, 16801 has been referenced in programming puzzles and challenges, particularly in languages like **APL** or **J**, where it may appear as a test case or benchmark value. Its inclusion in early computer systems has also led to its occasional appearance in retro computing communities, where enthusiasts discuss legacy hardware and software.

While not a widely recognized number in everyday contexts, 16801 remains an interesting figure in niche areas of technology and mathematics due to its historical and computational relevance. Its appearances in technical documentation and programming examples contribute to its lingering presence in specialized discussions.