The number 1642
1642 is a composite number with 4 divisors. Its prime factorisation is 2 × 821. Divisors (4): 1, 2, 821, 1642.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 1642: a semiprime: 2 × 821, the product of two primes.
- 2
1642 is composite. Its prime factorisation is
- 3
The divisors add up to 2466; without 1642 itself that is 824, so 1642 is deficient (824 is less than 1642). Euler's totient φ(1642) = 820 numbers up to 1642 share no factor with it.
- 4
The digits of 1642 add up to 13, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 29 steps to reach 1.
LaTeX source of the formulas on this page
\[ 1642 = 2 \times 821 \]
1642 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 2466 |
| Euler totient φ(n) | 820 |
| Square | 2696164 |
| Cube | 4427101288 |
| Square root | 40.521599 |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 29 |
| Scientific notation | 1.642 × |
1642 in other forms
| Form | Value |
|---|---|
| In words | one thousand six hundred and forty-two |
| Roman numerals | MDCXLII |
| Binary (base 2) | 11001101010 |
| Octal (base 8) | 3152 |
| Hexadecimal (base 16) | 66A |
| Base 3 | 2020211 |
| As time | 1642 seconds = 27 min 22 s |
Is 1642 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (1642 ÷ 2 = 821) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 1) | 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 4) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 4) | 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 2) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 4) | 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 3) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 10) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 1642 a prime number?
No. 1642 = 2 × 821, so it is divisible by 2.
What are the factors of 1642?
1, 2, 821, 1642.
What is 1642 in binary?
11001101010 (hexadecimal 66A, octal 3152).
What is the square root of 1642?
About 40.5216.
What is 1642 in Roman numerals?
MDCXLII.
Is 1642 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 1642?
1642 is a semiprime: 2 × 821, the product of two primes.