16975
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 28
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 24304
- Proper Divisor Sum (Aliquot Sum)
- 7329
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 11520
- Möbius Function
- 0
- Radical
- 3395
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 3
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
- 141
- 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
- no
- Odd
- yes
Appears in sequences
- a(n) = Sum_{k=0..2n-3} T(n,k) * T(n,k+3), with T given by A027082.at n=3A027112
- Odd 9-gonal (or enneagonal) numbers.at n=35A028991
- a(n) = ceiling((n + 7/10)^3).at n=24A034133
- Position of cubes in the EKG sequence (A064413).at n=25A140418
- a(n) = (2*n^3 + 5*n^2 - 17*n)/2.at n=24A162259
- Position of 5^n in A051037 (5-smooth numbers).at n=30A188427
- Number of (n+2)X7 0..1 arrays with all rows having a nonnegative second derivative, and all and columns having a positive second derivative in a quadratic least squares fit, with one and two element arrays taken as having a zero second derivative.at n=1A223651
- T(n,k)=Number of (n+2)Xk 0..1 arrays with all rows having a nonnegative second derivative, and all and columns having a positive second derivative in a quadratic least squares fit, with one and two element arrays taken as having a zero second derivative.at n=29A223652
- Number of 4Xn 0..1 arrays with all rows having a nonnegative second derivative, and all and columns having a positive second derivative in a quadratic least squares fit, with one and two element arrays taken as having a zero second derivative.at n=6A223654
- Number of second differences of arrays of length 4 of numbers in 0..n.at n=40A228219
- Self-inverse permutation of natural numbers: a(0) = 0, a(1) = 1, and for n > 1, if A117966(n) < 0, a(n) = A117967(1+a(-(A117966(n)))), otherwise a(n) = A117968(a(A117966(n)-1)).at n=40A246211
- a(n) = 10*n^2 + 4*n + 1.at n=41A272039
- p-INVERT of (1,0,2,0,2,0,2,0,2,0,...), where p(S) = (1 - S)^2.at n=13A292401
- Sum of the odd parts in the partitions of n into 7 parts.at n=33A309624
- a(n) is the largest term encountered on the path to 0 when iterating the map x -> x', and starting from x = A351255(n). Here x' means the arithmetic derivative of x, A003415.at n=36A351261
- Numbers k such that k and k+1 have the same sum of 5-smooth divisors.at n=11A355713
- a(n) = binomial(n+3, 4) + binomial(n+1, 3) + 1.at n=23A368881