Number reference
86 explained.
86: eighty-six, composite; factors, prime factorization, roots, binary, hexadecimal, and digit properties.
Identity and representations
- Written form
- eighty-six
- Classification
- composite
- Factors
- 1, 2, 43, 86
- Prime factorization
- 2 × 43
- Square root
- 9.273618
- Cube root
- 4.414005
- Binary
- 1010110
- Octal
- 126
- Hexadecimal
- 56
- Roman numeral
- LXXXVI
- Digit sum
- 14
- Digital root
- 5
What makes 86 notable
- Semiprime. 86 = 2 × 43, a product of exactly two primes. That gives it just four divisors, so it splits into equal groups in only two non-trivial ways.
86 in everyday use
Eighty-six is the atomic number of radon, the radioactive gas that seeps from granite bedrock into basements and is the second-leading cause of lung cancer after smoking. In American restaurant slang, to "86" an item is to remove it from the menu or refuse a customer; the origin is disputed. Maxwell Smart in Get Smart was Agent 86, and Interstate 86 runs through New York and Pennsylvania.
Eighty-six is 2 × 43 and a happy number: 64 + 36 = 100, and then 1. It can be written as the sum of three squares, 36 + 25 + 25. It is a nontotient, meaning no whole number has exactly 86 smaller numbers coprime to it. It has four divisors, and in binary it is 1010110.
Nearby numbers
How to read this page
The factor list shows every way 86 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 86 for contexts that do not use decimal.
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