1981
Everything about the number 1981 — its names, how to write it in other bases and numeral systems, and what makes it interesting mathematically.
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Names of 1981
| Nominal | 1981 |
| Cardinal | one thousand nine hundred eighty-one |
| Ordinal | 1,981st |
| This number as US currency | one thousand nine hundred eighty-one dollars |
Properties (and some facts) of 1981
| Is 1981 an odd number? | 1981 is an odd number |
| Is 1981 an even number? | 1981 is not an even number |
| Is 1981 a palindrome? | 1981 is not a palindrome |
| Is 1981 a triangle number? | 1981 is not a triangle number |
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1981 in other bases
| Base 2 (Binary) | 11110111101 |
| Base 3 (Ternary) | 2201101 |
| Base 4 (Quaternary) | 132331 |
| Base 5 (Quinary) | 30411 |
| Base 6 (Senary) | 13101 |
| Base 8 (Octal) | 3675 |
| Base 12 (Duodecimal) | 1191 |
| Base 16 (Hexadecimal) | 7BD |
| Base 20 (Vigesimal) | 4J1 |
Primes and factors tests for 1981
| Is 1981 a prime number? | 1981 is not a prime number |
| Is 1981 a perfect number? | 1981 is not a perfect number |
| Is 1981 a Mersenne prime? | 1981 is not a Mersenne prime |
| Is 1981 a Fermat prime? | 1981 is not a Fermat prime |
| Is 1981 a Fibonacci prime? | 1981 is not a Fibonacci prime |
| Is 1981 a partition prime? | 1981 is not a partition prime |
| Is 1981 a Pell prime? | 1981 is not a Pell prime |
| Prime Factors | Prime factors of 1981 |
1981 in other numeral systems
| 1981 in Roman numerals | MCMLXXXI |
| 1981 in Chinese numerals | 壹仟玖佰捌拾壹 |
| 1981 in Babylonian numerals |   |
| 1981 in Egyptian numerals | 𓆼𓍪𓎍𓏺 |
Roots and squares for 1981
| Is 1981 a square number? | 1981 is not a square number |
| Is 1981 a cube number? | 1981 is not a cube number |
| Square root of 1981 | 44.508426168536 |
| Cube root of 1981 | 12.559185985894 |
Recreational math for 1981
| Number 1981 reversed | 1891 |
| Sum of the digits | 19 |
| Number of digits | 4 |
Arithmetic tables for 1981
Other pages about 1981
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