Number reference
10 explained.
10: ten, composite, power of ten; factors, prime factorization, roots, binary, hexadecimal, and digit properties.
Identity and representations
- Written form
- ten
- Classification
- composite
- Factors
- 1, 2, 5, 10
- Prime factorization
- 2 × 5
- Square root
- 3.162278
- Cube root
- 2.154435
- Binary
- 1010
- Octal
- 12
- Hexadecimal
- A
- Roman numeral
- X
- Digit sum
- 1
- Digital root
- 1
What makes 10 notable
- Power of ten. 10 = 10^1, so shifting a decimal point by 1 place multiplies or divides by it.
- Triangular number. 10 is the 4th triangular number: it is the sum 1 + 2 + … + 4, the count of items in a triangle with 4 rows.
10 in everyday use
Ten is the base of the decimal system, almost certainly because humans count on ten fingers. It is the atomic number of neon and the number of pins in tenpin bowling, arranged in a triangle of four rows. A decade is ten years, a decathlon ten events, and the metric prefix deca- means ten of anything. A "perfect 10" comes from gymnastics scoring, which capped marks at ten until the code changed in 2006. The Ten Commandments and the ten-dollar bill keep it in daily speech.
Ten is the fourth triangular number: 1 + 2 + 3 + 4, which is exactly why bowling pins stack neatly in rows of one, two, three, and four. The Pythagoreans called this arrangement the tetractys and treated it as sacred. Ten is the first two-digit number, the product of the first two primes 2 and 5, and the smallest number that is the sum of two different primes in two ways: 3 + 7 and 5 + 5.
Nearby numbers
How to read this page
The factor list shows every way 10 splits into equal whole-number groups — 4 divisors in total. The prime factorisation is the compact form of that same information, and the base conversions restate 10 for contexts that do not use decimal.
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