991
Everything about the number 991 — its names, how to write it in other bases and numeral systems, and what makes it interesting mathematically.
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Names of 991
| Nominal | 991 |
| Cardinal | nine hundred ninety-one |
| Ordinal | 991st |
| This number as US currency | nine hundred ninety-one dollars |
Properties (and some facts) of 991
| Is 991 an odd number? | 991 is an odd number |
| Is 991 an even number? | 991 is not an even number |
| Is 991 a palindrome? | 991 is not a palindrome |
| Is 991 a triangle number? | 991 is not a triangle number |
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991 in other bases
| Base 2 (Binary) | 1111011111 |
| Base 3 (Ternary) | 1100201 |
| Base 4 (Quaternary) | 33133 |
| Base 5 (Quinary) | 12431 |
| Base 6 (Senary) | 4331 |
| Base 8 (Octal) | 1737 |
| Base 12 (Duodecimal) | 6A7 |
| Base 16 (Hexadecimal) | 3DF |
| Base 20 (Vigesimal) | 29B |
Primes and factors tests for 991
| Is 991 a prime number? | 991 is a prime number |
| Is 991 a perfect number? | 991 is not a perfect number |
| Is 991 a Mersenne prime? | 991 is not a Mersenne prime |
| Is 991 a Fermat prime? | 991 is not a Fermat prime |
| Is 991 a Fibonacci prime? | 991 is not a Fibonacci prime |
| Is 991 a partition prime? | 991 is not a partition prime |
| Is 991 a Pell prime? | 991 is not a Pell prime |
| Prime Factors | Prime factors of 991 |
991 in other numeral systems
| 991 in Roman numerals | CMXCI |
| 991 in Chinese numerals | 玖佰玖拾壹 |
| 991 in Babylonian numerals |   |
| 991 in Egyptian numerals | 𓍪𓎎𓏺 |
Roots and squares for 991
| Is 991 a square number? | 991 is not a square number |
| Is 991 a cube number? | 991 is not a cube number |
| Square root of 991 | 31.480152477394 |
| Cube root of 991 | 9.9699095472821 |
Recreational math for 991
| Number 991 reversed | 199 |
| Sum of the digits | 19 |
| Number of digits | 3 |
Arithmetic tables for 991
Other pages about 991
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