30 (number)
Natural number
From Wikipedia, the free encyclopedia
30 (thirty) is the natural number following 29 and preceding 31.
| ||||
|---|---|---|---|---|
| Cardinal | thirty | |||
| Ordinal | 30th (thirtieth) | |||
| Factorization | 2 × 3 × 5 | |||
| Divisors | 1, 2, 3, 5, 6, 10, 15, 30 | |||
| Greek numeral | Λ´ | |||
| Roman numeral | XXX, xxx | |||
| Binary | 111102 | |||
| Ternary | 10103 | |||
| Senary | 506 | |||
| Octal | 368 | |||
| Duodecimal | 2612 | |||
| Hexadecimal | 1E16 | |||
| Armenian | Լ | |||
| Hebrew | ל | |||
| Babylonian numeral | 𒌍 | |||
| Egyptian hieroglyph | 𓎐 | |||
In mathematics
30 is an even, composite, a pronic number, and a primorial.[1]
The SI prefix for 1030 is Quetta- (Q), and for 10−30 (i.e., the reciprocal of 1030) quecto (q). These numbers are the largest and smallest number to receive an SI prefix to date.
In other fields
Thirty is used (as –30–) to indicate the end of a newspaper (or broadcast) story, a copy editor's typographical notation
There are 30 days in the months April, June, September and November (and in unusual circumstances February—see February 30). Although the number of days in a month vary, 30 is used to estimate months elapsing.
30 years of marriage is marked by the pearl wedding anniversary.
History and literature
- Age 30 is when Jewish priests traditionally start their service (according to Numbers 4:3).
- One of the rallying cries of the 1960s student/youth protest movement was the slogan, "Don't trust anyone over thirty".
- In The Myth of Sisyphus the French existentialist Albert Camus comments that the age of thirty is a crucial period in the life of a man, for at that age he gains a new awareness of the meaning of time.