15724
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 27524
- Proper Divisor Sum (Aliquot Sum)
- 11800
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7860
- Möbius Function
- 0
- Radical
- 7862
- Omega Function (Ω)
- 3
- Little Omega Function (ω)
- 2
Special
- Factorial
- no
- Catalan Number
- no
- Bell Number
- no
- Motzkin Number
- no
- Primorial
- no
Figurate Numbers
- Fibonacci Number
- no
- Triangular Number
- no
- Perfect Square
- no
- 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
- 84
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- Prime Power
- no
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- yes
- Odd
- no
Appears in sequences
- Smallest a(n)>2 such that all integers strictly between a(n)-n and a(n) are composite.at n=40A075741
- Pseudo-random numbers: MS C 6.0 version.at n=5A084275
- Minimal exponents m such that the fractional part of (Pi-2)^m obtains a maximum (when starting with m=1).at n=14A153719
- Numbers k such that the fractional part of (Pi-2)^k is greater than 1-(1/k).at n=8A153720
- First string of 43 consecutive composite numbers.at n=40A177949
- Number of nXnXn 0..6 triangular arrays with each element x equal to the number its neighbors equal to 6,6,0,0,1,1,1 for x=0,1,2,3,4,5,6.at n=5A197852
- Number of 0..7 arrays x(0..n-1) of n elements with each no smaller than the sum of its previous elements modulo 8.at n=5A200250
- Number of 0..n arrays x(0..5) of 6 elements with each no smaller than the sum of its previous elements modulo (n+1).at n=6A200255
- Number of n X 2 0..3 arrays with no element equal the average of immediate neighbors vertically above, diagonally above and left, and horizontally left of it.at n=3A209013
- Number of nX4 0..3 arrays with no element equal the average of immediate neighbors vertically above, diagonally above and left, and horizontally left of it.at n=1A209015
- T(n,k)=Number of nXk 0..3 arrays with no element equal the average of immediate neighbors vertically above, diagonally above and left, and horizontally left of it.at n=11A209019
- T(n,k)=Number of nXk 0..3 arrays with no element equal the average of immediate neighbors vertically above, diagonally above and left, and horizontally left of it.at n=13A209019
- Number of 2 X 2 matrices having all elements in {-n,...n} and determinant 4.at n=30A209988
- Number of nX3 arrays of the minimum value of corresponding elements and their horizontal, vertical, diagonal or antidiagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and nonincreasing columns, 0..2 nX3 array.at n=10A219910
- Number of nX6 arrays of the minimum value of corresponding elements and their horizontal, diagonal or antidiagonal neighbors in a random 0..3 nX6 array.at n=1A220760
- T(n,k) = Number of n X k arrays of the minimum value of corresponding elements and their horizontal, diagonal or antidiagonal neighbors in a random 0..3 n X k array.at n=22A220761
- Number of 2Xn arrays of the minimum value of corresponding elements and their horizontal, diagonal or antidiagonal neighbors in a random 0..3 2Xn array.at n=5A220762
- Where record values occur in A276781, when starting from A276781(2)=1.at n=41A276782
- a(n) is the smallest integer k > n such that (k+1)(k+2)...(2k-2n+1)/(k(k-1)...(k-n+1)) is an integer.at n=40A290791
- Expansion of 1/(1 + Sum_{i>=1} q^(i^2)/Product_{j=1..i} (1 + q^(2*j))).at n=34A294408