The number 21470
21470 is a composite number with 16 divisors. Its prime factorisation is 2 × 5 × 19 × 113. Divisors (16): 1, 2, 5, 10, 19, 38, 95, 113, 190, 226, 565, 1130, 2147, 4294, 10735, 21470.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21470: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
21470 is composite. Its prime factorisation is
- 3
The divisors add up to 41040; without 21470 itself that is 19570, so 21470 is deficient (19570 is less than 21470). Euler's totient φ(21470) = 8064 numbers up to 21470 share no factor with it.
- 4
The digits of 21470 add up to 14, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 87 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21470 = 2 \times 5 \times 19 \times 113 \]
21470 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 41040 |
| Euler totient φ(n) | 8064 |
| Square | 460960900 |
| Cube | 9896830523000 |
| Square root | 146.526448 |
| Digit sum / digital root | 14 / 5 |
| Collatz steps to 1 | 87 |
| Scientific notation | 2.147 × |
21470 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand four hundred and seventy |
| Binary (base 2) | 101001111011110 |
| Octal (base 8) | 51736 |
| Hexadecimal (base 16) | 53DE |
| Base 3 | 1002110012 |
| As time | 21470 seconds = 5 h 57 min 50 s |
Is 21470 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21470 ÷ 2 = 10735) | 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 | Yes (21470 ÷ 5 = 4294) | 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 5) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (21470 ÷ 10 = 2147) | 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 2) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21470 a prime number?
No. 21470 = 2 × 5 × 19 × 113, so it is divisible by 2.
What are the factors of 21470?
1, 2, 5, 10, 19, 38, 95, 113, 190, 226, 565, 1130, 2147, 4294, 10735, 21470.
What is 21470 in binary?
101001111011110 (hexadecimal 53DE, octal 51736).
What is the square root of 21470?
About 146.5264.
Is 21470 divisible by 3?
No. Its digits add up to 14, which is not a multiple of 3.
What is special about the number 21470?
21470 is a happy number: repeatedly adding the squares of its digits reaches 1.