25
domain: N
Properties
Digital Properties
- Digit Count
- 2
- Digit Sum
- 7
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- yes
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 3
- Divisor Sum
- 31
- Proper Divisor Sum (Aliquot Sum)
- 6
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 20
- Möbius Function
- 0
- Radical
- 5
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 1
Special
- Factorial
- no
- Catalan Number
- no
- Bell Number
- no
- Motzkin Number
- no
- Primorial
- no
Figurate Numbers
- Fibonacci Number
- no
- Triangular Number
- no
- Perfect Square
- yes
- Perfect Cube
- no
- Pentagonal Number
- no
- Hexagonal Number
- no
- Lucas Number
- no
- Tetrahedral Number
- no
- Pell Number
- no
- Tribonacci Number
- no
- Pronic Number
- no
Recreational
- Happy Number
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 23
- Smith Number
- no
Classification
- Natural
- yes
- Even
- no
- Odd
- yes
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- Squarefree Number
- no
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- yes
- Achilles Number
- no
- Perfect Power
- yes
- Smooth Number
- yes
- Carmichael Number
- no
Names
- German
- fünfundzwanzig· ordinal: fünfundzwanzigste
- English
- twenty-five· ordinal: twenty-fifth
- Spanish
- veinticinco· ordinal: 25º
- French
- vingt-cinq· ordinal: vingt-cinqième
- Italian
- venticinque· ordinal: 25º
- Latin
- viginti quinque· ordinal: 25.
- Portuguese
- vinte e cinco· ordinal: 25º
Appears in sequences
- Number of ways of making change for n cents using coins of 1, 2, 5, 10 cents.at n=16A000008
- Smallest prime power >= n.at n=23A000015
- Smallest prime power >= n.at n=24A000015
- Number of positive integers <= 2^n of form x^2 + 16*y^2.at n=7A000018
- The positive integers. Also called the natural numbers, the whole numbers or the counting numbers, but these terms are ambiguous.at n=24A000027
- Let k = p_1^e_1 p_2^e_2 p_3^e_3 ... be the prime factorization of n. Sequence gives k such that the sum of the numbers of 1's in the binary expansions of e_1, e_2, e_3, ... is odd.at n=13A000028
- A Beatty sequence: a(n) = floor(n/(e-2)).at n=17A000062
- Odious numbers: numbers with an odd number of 1's in their binary expansion.at n=12A000069
- Number of odd integers <= 2^n of form x^2 + y^2.at n=6A000074
- Lower Wythoff sequence (a Beatty sequence): a(n) = floor(n*phi), where phi = (1+sqrt(5))/2 = A001622.at n=15A000201
- a(8i+j) = 13i + a(j), where 1<=j<=8.at n=15A000202
- Number of positive integers <= 2^n of form x^2 + 3 y^2.at n=6A000205
- A Beatty sequence: floor(n*(e-1)).at n=14A000210
- Take sum of squares of digits of previous term; start with 5.at n=1A000221
- Construct a triangle as in A036262. Sequence is one less than the position of the first number larger than 2 in the n-th row (n-th difference).at n=4A000232
- Construct a triangle as in A036262. Sequence is one less than the position of the first number larger than 2 in the n-th row (n-th difference).at n=8A000232
- 3rd power of rooted tree enumerator; number of linear forests of 3 rooted trees.at n=3A000242
- a(n) = 2^n - n - 2.at n=3A000247
- Remove all factors of 2 from n; or largest odd divisor of n; or odd part of n.at n=24A000265
- Remove all factors of 2 from n; or largest odd divisor of n; or odd part of n.at n=49A000265