15446
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 23172
- Proper Divisor Sum (Aliquot Sum)
- 7726
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7722
- Möbius Function
- 1
- Radical
- 15446
- Omega Function (Ω)
- 2
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 53
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- Squarefree Number
- yes
- 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
- a(n) = Sum_[k unrelated to n and k<n] a(k) = Sum_[k < n such that GCD(k,n) != 1 and k does not divide n ] a(k); a(1) = a(2) = a(3) = a(4) = 1.at n=33A118657
- a(n) = sum(stirling1(n,k)^2*k!, k=0..n).at n=5A192559
- Number of 0..7 arrays x(0..n-1) of n elements with each no smaller than the sum of its four previous neighbors modulo 8.at n=5A200468
- Number of 0..n arrays x(0..5) of 6 elements with each no smaller than the sum of its four previous neighbors modulo (n+1).at n=6A200470
- Number of partitions p of n not including ceiling(mean(p)) as a part.at n=39A241337
- Divide the positive integers into subsets of lengths given by successive primes. a(n) is the sum of primes contained in the n-th subset.at n=25A344718
- Array read by ascending antidiagonals: A(n, k) = (-1)^(n + k) * Sum_{j=0..k} j! * Stirling1(n, j) * Stirling1(k, j).at n=60A379820