| 25 | 20 | 5 |
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25 (twenty-five) is the natural number following 24 and preceding 26. "Twenty" redirects here For the village in England, see Twenty Lincolnshire. This article discusses the number five. For the year 5 AD see 5. In Mathematics, a natural number (also called counting number) can mean either an element of the set (the positive Integers or an 24 ( twenty-four) is the Natural number following 23 and preceding 25. 26 ( twenty-six) is the Natural number following 25 and preceding 27.
| Cardinal | 25 twenty five |
| Ordinal | 25th twenty-fifth |
| Factorization | ![]() |
| Divisors | 1, 5, 25 |
| Roman numeral | XXV |
| Binary | 11001 |
| Hexadecimal | 19 |
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It is a square number, being 5² = 5 × 5. 19 ( nineteen) is the Natural number following 18 and preceding 20. "Twenty" redirects here For the village in England, see Twenty Lincolnshire. 21 ( twenty-one) is the Natural number following 20 and preceding 22. 22 ( twenty-two) is the Natural number following 21 and preceding 23. This article is about the number 23 For the year see 23. For the movies see 23 (film and The Number 23. 24 ( twenty-four) is the Natural number following 23 and preceding 25. 26 ( twenty-six) is the Natural number following 25 and preceding 27. 27 ( twenty-seven) is the Natural number following 26 and preceding 28. 28 ( twenty-eight) is the Natural number following 27 and preceding 29. 29 ( twenty-nine) is the Natural number following 28 and preceding 30. 30 ( thirty) is the Natural number following 29 and preceding 31. This is a list of articles about Numbers ( not about Numerals. The integers (from the Latin integer, literally "untouched" hence "whole" the word entire comes from the same origin but via French "Twenty" redirects here For the village in England, see Twenty Lincolnshire. 30 ( thirty) is the Natural number following 29 and preceding 31. 40 ( forty) is the Natural number following 39 and preceding 41. This article discusses the number fifty. For the year 50 CE see 50. 60 ( sixty) is the Natural number following 59 and preceding 61. 70 ( seventy) is the Natural number following 69 and preceding 71. 80 ( eighty) is the Natural number following 79 and preceding 81. 90 ( ninety) is the Natural number preceded by 89 and followed by 91. This article describes cardinal numbers in mathematics For cardinals in linguistics see Names of numbers in English. In Set theory, an ordinal number, or just ordinal, is the Order type of a Well-ordered set. In Mathematics, factorization ( also factorisation in British English) or factoring is the decomposition of an object (for In Mathematics, a divisor of an Integer n, also called a factor of n, is an integer which evenly divides n without Roman numerals are a Numeral system originating in ancient Rome, adapted from Etruscan numerals. The binary numeral system, or base-2 number system, is a Numeral system that represents numeric values using two symbols usually 0 and 1. In Mathematics and Computer science, hexadecimal (also base -, hexa, or hex) is a Numeral system with a In Mathematics, a square number, sometimes also called a Perfect square, is an Integer that can be written as the square of some other This article discusses the number five. For the year 5 AD see 5. It is the smallest square that is also a sum of two squares: 25 = 3² + 4². Hence it often appears in demonstrations of the Pythagorean theorem. In Mathematics, the Pythagorean theorem ( American English) or Pythagoras' theorem ( British English) is a relation in Euclidean geometry
25 is a centered octagonal number and an automorphic number. A centered octagonal number is a centered Figurate number that represents an Octagon with a dot in the center and all other dots surrounding the center In Mathematics an automorphic number (sometimes referred to as a circular number) is a Number whose square "ends" in the number itself
25 has an aliquot sum of 6 and is the first number to have an aliquot sequence that does not culminate in 0 through a prime. In Mathematics, and specifically in Number theory, a divisor function is an Arithmetical function related to the Divisors of an Integer In Mathematics, an aliquot sequence is a recursive sequence in which each term is the sum of the Proper divisors of the previous term In Mathematics, a prime number (or a prime) is a Natural number which has exactly two distinct natural number Divisors 1
It is the smallest base 10 Friedman number as it can be expressed by its own numbers: 5². The decimal ( base ten or occasionally denary) Numeral system has ten as its base. A Friedman number is an Integer which in a given base is the result of an expression using all its own digits in combination with any of the four basic arithmetic operators
It is also a Cullen number. In Mathematics, a Cullen number is a Natural number of the form n · 2 n + 1 (written C n) 25 is the smallest pseudoprime satisfying the congruence 7n = 7 mod n. A pseudoprime is a Probable prime (an Integer which shares a property common to all Prime numbers which is not actually prime It is also a Somer pseudoprime based on 6.
25 is the smallest aspiring number — a composite non-sociable number whose aliquot sequence does not terminate. In Mathematics, an aliquot sequence is a recursive sequence in which each term is the sum of the Proper divisors of the previous term Sociable numbers are generalizations of the concepts of Amicable numbers and Perfect numbers A set of sociable numbers is a kind of Aliquot sequence, or In Mathematics, an aliquot sequence is a recursive sequence in which each term is the sum of the Proper divisors of the previous term
According to the Shapiro inequality 25 is the least odd integer n such that there exist
such that

where xn + 1 = x1,xn + 2 = x2. In Mathematics, the Shapiro inequality is an Inequality due to H
Within base 10 one can readily test for divisibility by 25 by seeing if the last two digits of the number match 25, 50, 75 or 00.
11:25 is a magic number
Twenty five is:
25 A.D., 25 B.C., 1925, 2025, etc. Year 25 was a Common year starting on Monday (link will display the full calendar of the Julian calendar. Year 25 BC was a Leap year starting on Tuesday (link will display the full calendar of the Julian calendar. Year 1925 ( MCMXXV) was a Common year starting on Thursday (link will display the full calendar of the Gregorian calendar. 2025 ( MMXXV) will be a Common year starting on Wednesday of the Gregorian Calendar.
Christmas is on the 25th of December