2101

2101 is a natural number that lies between 2100 and 2102. In its prime factorization it is 11 multiplied by 191, making 2101 a semiprime. Its positive divisors are 1, 11, 191, and 2101. In various bases it is represented as follows: binary 100000110101, octal 4065, and hexadecimal 0x835. The Roman numeral for 2101 is MMCI. The sum of its decimal digits is 4, which makes 2101 congruent to 1 modulo 3 and 4 modulo 9.

As a calendar year, 2101 refers to the year 2101 CE in the Gregorian system. It is the first year of the 22nd century, a point far in the future relative to the present. In fiction and futurism, 2101 is commonly used as a distant setting to explore speculative technologies, society, and governance, though no real-world events from that year are documented.

Beyond mathematics and calendars, 2101 can appear as an identifier or label in various domains, such as catalog numbers, part numbers, or model designations. Its features as a semiprime and its distinct digit pattern sometimes make it a convenient reference in examples or simulations that require a nontrivial four-digit number.