10
X
1010
The number 10 — factors and divisors
Deficient
10 = 2 × 5. It has 4 divisors, adding up to 18.
Its divisors, itself excluded, add up to less than the number.
Families it belongs to
Triangular
The running total of 1, 2, 3 … — the dots stack into a triangle.
Laid out as dots
It fits as 2 × 5. The more divisors, the closer to a square.
- Prime factors
- 2 × 5
- Divisors
- 1, 2, 5, 10
- Sum of divisors
- 18
- Sum without itself
- 8
- Coprime below it
- 4
- Digit sum
- 1
- Digital root
- 1
- Roman numeral
- X
- Binary
- 1010
- Octal
- 12
- Hexadecimal
- A
- Base 36
- A
- Bits
- 4 bits
- Collatz steps
- 6 steps · peaks at 16
- Prime before
- 7
- Prime after
- 11
The grid
Ten per row, twenty rows. The filled cells are primes — you can see the multiples of 2 and 5 drop out in columns.
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Numbers either side
How to read this
- The prime factors are what the number is made of. The count and sum of divisors both follow from them.
- Add the divisors, take the number away, and you get perfect, abundant or deficient.
- The length of the binary form is the bit count. 255 taking eight digits is what a byte is.
- Collatz: halve it if even, triple it and add one if odd. The count is how many moves reach 1.
Frequently asked questions
Q. Is 10 a prime number?
No. It breaks down into 2 × 5.
Q. What are the divisors of 10?
1, 2, 5, 10 — 4 divisors in all, adding up to 18.
Q. How is 10 written in binary?
1010, which is 4 bits. In hexadecimal it is A.
Q. How many Collatz steps does 10 take?
It reaches 1 in 6, peaking at 16 on the way.