25 (twenty-five) is the natural number following 24 and preceding 26.

It is a square number, being 5² = 5 × 5. It is the smallest square that is also a sum of two (non-zero) squares: 25 = 3² + 4². Hence it often appears in illustrations of the Pythagorean theorem.

25 is a centered octagonal number, a centered square number, and an automorphic number.

25 percent is equal to 1/4.

25 has an aliquot sum of 6 and number 6 is the first (or smallest) number to have an aliquot sequence that does not culminate in 0 through a prime. Twenty-five is the aliquot sum of three integers; 95, 119, and 143. Twenty-five is the second composite member of the 6-aliquot tree.

It is the smallest base 10 Friedman number as it can be expressed by its own numbers: 5².

It is also a Cullen number. 25 is the smallest pseudoprime satisfying the congruence 7ⁿ = 7 mod n.

25 is the smallest aspiring number — a composite non-sociable number whose aliquot sequence does not terminate.

According to the Shapiro inequality, 25 is the least odd integer n such that there exist Failed to parse (Missing texvc executable; please see math/README to configure.): x_1, x_2, \dots, x_n

An anniversary is a day that commemorates or celebrates a past event that occurred on the same day of the year as the initial event. For example, the first event is the initial occurrence or, if planned, the inaugural of the event. One year later would be the first anniversary of that event. The word was first used for Catholic feasts to commemorate saints.

The Latin phrase dies natalis (literally "birth day") has become a common term, adopted in many languages, especially in intellectual and institutional circles, for the anniversary of the founding ("legal or statutory birth") of an institution, such as an alma mater (college or other school). Even in ancient Rome, we know of the [dies] Aquilae natalis ("birthday of the eagle", anniversary of the official founding of a legion).

Most countries around the world celebrate national anniversaries, for example the United States Bicentennial. These could be the date of independence of the nation or the adoption of a new constitution or form of government. The important dates in a sitting monarch's reign may also be commemorated, an event often referred to as a 'Jubilee'.

David John "Dave" Matthews (born January 9, 1967) is a South African-American musician and actor, best known as the lead vocalist, songwriter, and guitarist for the Dave Matthews Band. He performs mainly with acoustic guitar and favors rhythm rather than solos in his playing.

David John Matthews was born in Johannesburg, South Africa, the third of four children of parents John and Valerie Matthews. At two years old, Matthews' family moved to Yorktown Heights in Westchester County, New York, where his father, a physicist, started working for IBM.

In 1974, the family moved to Cambridge, England, for a year before returning to New York, where his father died from lung cancer in 1977. Biographer Nevin Martell argues that Dave's father's death may be an impetus for his "carpe diem" lyrics. At some point while residing in New York, Matthews attended his first concert, when his mother took him to a performance by Pete Seeger. The family moved back to Johannesburg, South Africa, in 1977.

Upon Matthews' graduation from St Stithians College high school in 1985, he was faced with conscription into the South African military just as civil disobedience to the practice was becoming widespread. A Quaker (and consequently pacifist), Matthews left South Africa to avoid service.