The number 1620
1620 is a composite number with 30 divisors. Its prime factorisation is × × 5. Divisors (30): 1, 2, 3, 4, 5, 6, 9, 10, 12, 15, 18, 20, 27, 30, 36, 45 … 1620.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 1620: a Harshad number: divisible by its digit sum 9.
- 2
1620 is composite. Its prime factorisation is
- 3
The divisors add up to 5082; without 1620 itself that is 3462, so 1620 is abundant (3462 is more than 1620). Euler's totient φ(1620) = 432 numbers up to 1620 share no factor with it.
- 4
The digits of 1620 add up to 9, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 29 steps to reach 1.
LaTeX source of the formulas on this page
\[ 1620 = 2^{2} \times 3^{4} \times 5 \]1620 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 30 |
| Sum of divisors | 5082 |
| Euler totient φ(n) | 432 |
| Square | 2624400 |
| Cube | 4251528000 |
| Square root | 40.249224 (= 18√5) |
| Digit sum / digital root | 9 / 9 |
| Collatz steps to 1 | 29 |
| Scientific notation | 1.62 × |
1620 in other forms
| Form | Value |
|---|---|
| In words | one thousand six hundred and twenty |
| Roman numerals | MDCXX |
| Binary (base 2) | 11001010100 |
| Octal (base 8) | 3124 |
| Hexadecimal (base 16) | 654 |
| Base 3 | 2020000 |
| As time | 1620 seconds = 27 min 0 s |
Is 1620 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (1620 ÷ 2 = 810) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (1620 ÷ 3 = 540) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (1620 ÷ 4 = 405) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (1620 ÷ 5 = 324) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (1620 ÷ 6 = 270) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 3) | 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 4) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (1620 ÷ 9 = 180) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (1620 ÷ 10 = 162) | 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 | Yes (1620 ÷ 12 = 135) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 1620 a prime number?
No. 1620 = × × 5, so it is divisible by 2.
What are the factors of 1620?
1, 2, 3, 4, 5, 6, 9, 10, 12, 15, 18, 20, 27, 30, 36, 45, 54, 60, 81, 90, 108, 135, 162, 180, 270, 324, 405, 540, 810, 1620.
What is 1620 in binary?
11001010100 (hexadecimal 654, octal 3124).
What is the square root of 1620?
About 40.2492, exactly 18√5.
What is 1620 in Roman numerals?
MDCXX.
Is 1620 divisible by 3?
Yes. Its digits add up to 9, a multiple of 3.
What is special about the number 1620?
1620 is a Harshad number: divisible by its digit sum 9.