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Instantly identify prime, composite, or special numbers. Supports batch checking and mathematical property analysis.
Enter a number to check
Least Common Multiple (LCM) Calculator
Quickly calculate the least common multiple (LCM) of two or more integers. Supports space-separated number list input.
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Quickly calculate the area of a circle by entering the radius, diameter, or circumference. Supports custom units and precision settings.
Android Permission Lookup & Reference Guide
Provides developers and users with instant plain English names and functional descriptions for standard Android permission strings.
Inverse Trigonometric Function Calculator
Accurately calculate radian values for inverse trig functions like arcsin and arccos. Supports 6 function types and custom decimal precision.
Least Common Multiple (LCM) Calculator
Quickly calculate the least common multiple (LCM) of two or more integers. Supports space-separated number list input.
Circle Area Calculator
Quickly calculate the area of a circle by entering the radius, diameter, or circumference. Supports custom units and precision settings.
Android Permission Lookup & Reference Guide
Provides developers and users with instant plain English names and functional descriptions for standard Android permission strings.
Inverse Trigonometric Function Calculator
Accurately calculate radian values for inverse trig functions like arcsin and arccos. Supports 6 function types and custom decimal precision.
Trigonometry Calculator
Calculate six trigonometric functions from radian values with custom decimal precision.
Struggling to quickly determine the properties of an integer? This tool uses number theory algorithms to accurately analyze your input and classify it into one of three categories: prime, composite, or other. A prime number is a natural number greater than 1 that is only divisible by 1 and itself (e.g., 2, 3). A composite number is a positive integer that has at least one divisor other than 1 and itself (e.g., 4, 6). All other numbers, such as 1, 0, and negative numbers, are classified as special categories (neither).
Q: Is 1 a prime number?
No. According to mathematical definitions, 1 is neither prime nor composite. The tool will classify it as "Other".
Q: Can negative numbers be identified as prime numbers?
No. The definition of prime numbers only applies to natural numbers greater than 1. All negative numbers and 0 are categorized as "Other".
The tool only accepts integer inputs; non-integer values will cause calculation errors. We recommend processing no more than 100 numbers at a time. Extremely large integers (exceeding 10^15) may impact calculation efficiency. The classification strictly follows mathematical definitions and does not apply to non-standard values like complex numbers.
For math education, we recommend using this tool alongside definition explanations: entering "2 9 15" demonstrates typical examples of primes [2] and composites [9, 15]. Developers should note that this tool does not provide an API; for large-scale batch processing, we recommend submitting in smaller batches. All calculations are performed locally in your browser, ensuring zero data upload risks.
