The number 1615
1615 is a composite number with 8 divisors. Its prime factorisation is 5 × 17 × 19. Divisors (8): 1, 5, 17, 19, 85, 95, 323, 1615.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
1615 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
1615 is composite. Its prime factorisation is
- 3
The divisors add up to 2160; without 1615 itself that is 545, so 1615 is deficient (545 is less than 1615). Euler's totient φ(1615) = 1152 numbers up to 1615 share no factor with it.
- 4
The digits of 1615 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 73 steps to reach 1.
LaTeX source of the formulas on this page
\[ 1615 = 5 \times 17 \times 19 \]
1615 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 2160 |
| Euler totient φ(n) | 1152 |
| Square | 2608225 |
| Cube | 4212283375 |
| Square root | 40.187063 |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 73 |
| Scientific notation | 1.615 × |
1615 in other forms
| Form | Value |
|---|---|
| In words | one thousand six hundred and fifteen |
| Roman numerals | MDCXV |
| Binary (base 2) | 11001001111 |
| Octal (base 8) | 3117 |
| Hexadecimal (base 16) | 64F |
| Base 3 | 2012211 |
| As time | 1615 seconds = 26 min 55 s |
Is 1615 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | No (remainder 1) | 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 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (1615 ÷ 5 = 323) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 1) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 5) | 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 7) | 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 5) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 9) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 1615 a prime number?
No. 1615 = 5 × 17 × 19, so it is divisible by 5.
What are the factors of 1615?
1, 5, 17, 19, 85, 95, 323, 1615.
What is 1615 in binary?
11001001111 (hexadecimal 64F, octal 3117).
What is the square root of 1615?
About 40.1871.
What is 1615 in Roman numerals?
MDCXV.
Is 1615 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 1615?
It is a composite number with 8 divisors.