Number reference
30 explained.
30: thirty, composite; factors, prime factorization, roots, binary, hexadecimal, and digit properties.
Identity and representations
- Written form
- thirty
- Classification
- composite
- Factors
- 1, 2, 3, 5, 6, 10, 15, 30
- Prime factorization
- 2 × 3 × 5
- Square root
- 5.477226
- Cube root
- 3.107233
- Binary
- 11110
- Octal
- 36
- Hexadecimal
- 1E
- Roman numeral
- XXX
- Digit sum
- 3
- Digital root
- 3
What makes 30 notable
- Factor structure. 30 breaks down into 3 distinct primes (2, 3, 5) and has 8 divisors in total, so it can be split into equal whole-number groups 6 ways beyond 1 and itself.
30 in everyday use
Thirty is the number of days in April, June, September, and November, and half an hour is 30 minutes. It is the atomic number of zinc. A thirtieth anniversary is pearl, 30 is the second point in a tennis game, and a 30-second slot is the standard unit of television advertising. Sine of 30 degrees is exactly one half, the cleanest value in trigonometry after 0 and 90.
Thirty is the product of the first three primes, 2 × 3 × 5. It has a remarkable property: every number below it that shares no factor with it — 7, 11, 13, 17, 19, 23, 29 — is prime, and 30 is the largest number for which that is true. It is also a square pyramidal number, 1 + 4 + 9 + 16, and has eight divisors.
Nearby numbers
How to read this page
The factor list shows every way 30 splits into equal whole-number groups — 8 divisors in total. The prime factorisation is the compact form of that same information, and the base conversions restate 30 for contexts that do not use decimal.
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