9
Everything about the number 9 — its names, how to write it in other bases and numeral systems, and what makes it interesting mathematically.
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Names of 9
| Nominal | 9 |
| Cardinal | nine |
| Ordinal | 9th |
| This number as US currency | nine dollars |
Properties (and some facts) of 9
| Is 9 an odd number? | 9 is an odd number |
| Is 9 an even number? | 9 is not an even number |
| Is 9 a palindrome? | 9 is a palindrome |
| Is 9 a triangle number? | 9 is not a triangle number |
| Factorial (9!) of the number 9 | 362880 |
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9 in other bases
| Base 2 (Binary) | 1001 |
| Base 3 (Ternary) | 100 |
| Base 4 (Quaternary) | 21 |
| Base 5 (Quinary) | 14 |
| Base 6 (Senary) | 13 |
| Base 8 (Octal) | 11 |
| Base 12 (Duodecimal) | 9 |
| Base 16 (Hexadecimal) | 9 |
| Base 20 (Vigesimal) | 9 |
Primes and factors tests for 9
| Is 9 a prime number? | 9 is not a prime number |
| Is 9 a perfect number? | 9 is not a perfect number |
| Is 9 a Mersenne prime? | 9 is not a Mersenne prime |
| Is 9 a Fermat prime? | 9 is not a Fermat prime |
| Is 9 a Fibonacci prime? | 9 is not a Fibonacci prime |
| Is 9 a partition prime? | 9 is not a partition prime |
| Is 9 a Pell prime? | 9 is not a Pell prime |
| Prime Factors | Prime factors of 9 |
9 in other numeral systems
| 9 in Roman numerals | IX |
| 9 in Chinese numerals | 玖 |
| 9 in Babylonian numerals |  |
| 9 in Egyptian numerals | 𓐂 |
Roots and squares for 9
| Is 9 a square number? | 9 is a square number |
| Is 9 a cube number? | 9 is not a cube number |
| Square root of 9 | 3 |
| Cube root of 9 | 2.0800838230519 |
Recreational math for 9
| Number 9 reversed | 9 |
| Sum of the digits | 9 |
| Number of digits | 1 |
Arithmetic tables for 9
Other pages about 9
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