30 (number)

30 is an even, composite, a pronic number, and a primorial. 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 • The number of 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. • In years of marriage, 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. ==References==