The number 1982
1982 is a composite number with 4 divisors. Its prime factorisation is 2 × 991. Divisors (4): 1, 2, 991, 1982.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 1982: a semiprime: 2 × 991, the product of two primes.
- 2
1982 is composite. Its prime factorisation is
- 3
The divisors add up to 2976; without 1982 itself that is 994, so 1982 is deficient (994 is less than 1982). Euler's totient φ(1982) = 990 numbers up to 1982 share no factor with it.
- 4
The digits of 1982 add up to 20, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 99 steps to reach 1.
LaTeX source of the formulas on this page
\[ 1982 = 2 \times 991 \]
1982 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 2976 |
| Euler totient φ(n) | 990 |
| Square | 3928324 |
| Cube | 7785938168 |
| Square root | 44.519659 |
| Digit sum / digital root | 20 / 2 |
| Collatz steps to 1 | 99 |
| Scientific notation | 1.982 × |
1982 in other forms
| Form | Value |
|---|---|
| In words | one thousand nine hundred and eighty-two |
| Roman numerals | MCMLXXXII |
| Binary (base 2) | 11110111110 |
| Octal (base 8) | 3676 |
| Hexadecimal (base 16) | 7BE |
| Base 3 | 2201102 |
| As time | 1982 seconds = 33 min 2 s |
Is 1982 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (1982 ÷ 2 = 991) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 2) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 2) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 2) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 2) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 1) | A number is divisible by 7 if double the last digit and subtract it from the rest: the result is a multiple of 7. |
| 8 | No (remainder 6) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 2) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 2) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 2) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 2) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 1982 a prime number?
No. 1982 = 2 × 991, so it is divisible by 2.
What are the factors of 1982?
1, 2, 991, 1982.
What is 1982 in binary?
11110111110 (hexadecimal 7BE, octal 3676).
What is the square root of 1982?
About 44.5197.
What is 1982 in Roman numerals?
MCMLXXXII.
Is 1982 divisible by 3?
No. Its digits add up to 20, which is not a multiple of 3.
What is special about the number 1982?
1982 is a semiprime: 2 × 991, the product of two primes.