64
LXIV
1000000
The number 64 — factors and divisors
Deficient
64 = 2⁶. It has 7 divisors, adding up to 127.
Its divisors, itself excluded, add up to less than the number.
Families it belongs to
Square
A number times itself — the dots lay out as a square.
Cube
A number times itself three times — the dots stack into a cube.
Power of two
Two multiplied by itself. Every extra bit doubles it.
Laid out as dots
It fits as 8 × 8. The more divisors, the closer to a square.
- Prime factors
- 2⁶
- Divisors
- 1, 2, 4, 8, 16, 32, 64
- Sum of divisors
- 127
- Sum without itself
- 63
- Coprime below it
- 32
- Digit sum
- 10
- Digital root
- 1
- Roman numeral
- LXIV
- Binary
- 1000000
- Octal
- 100
- Hexadecimal
- 40
- Base 36
- 1S
- Bits
- 7 bits
- Collatz steps
- 6 steps · peaks at 64
- Prime before
- 61
- Prime after
- 67
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 64 a prime number?
No. It breaks down into 2⁶.
Q. What are the divisors of 64?
1, 2, 4, 8, 16, 32, 64 — 7 divisors in all, adding up to 127.
Q. How is 64 written in binary?
1000000, which is 7 bits. In hexadecimal it is 40.
Q. How many Collatz steps does 64 take?
It reaches 1 in 6, peaking at 64 on the way.