17481
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 23312
- Proper Divisor Sum (Aliquot Sum)
- 5831
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 11652
- Möbius Function
- 1
- Radical
- 17481
- 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
- no
- 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
- no
- Odd
- yes
Appears in sequences
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 88.at n=27A031586
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 70 ones.at n=35A031838
- Numbers whose base-4 representation has exactly 8 runs.at n=4A043599
- Numbers n such that number of runs in the base 4 representation of n is congruent to 1 mod 7.at n=25A043844
- Numbers n such that number of runs in the base 4 representation of n is congruent to 0 mod 8.at n=4A043850
- Numbers n such that number of runs in the base 4 representation of n is congruent to 8 mod 9.at n=4A043866
- Numbers k such that number of runs in the base 4 representation of k is congruent to 8 mod 10.at n=4A043875
- Number of positive integers <= 2^n of form x^2 + 9 y^2.at n=17A054153
- Semiprimes in A056109.at n=33A113528
- Triangle T(n, k) = coefficients of p(x,n), where p(x,n) = ((1-x)^(2*n+1)/x^n) * Sum_{j >= n} ( (2*j+1)^n * binomial(j, n) * x^j ), read by rows.at n=34A156654
- Expansion of (1-x+x^2)/((1-x)(1-x-x^2-x^3)).at n=16A202012
- Number of (n+1) X (1+1) 0..2 arrays with the maximum plus the lower median minus the upper median minus the minimum of every 2 X 2 subblock equal.at n=4A236802
- Number of (n+1)X(5+1) 0..2 arrays with the maximum plus the lower median minus the upper median minus the minimum of every 2X2 subblock equal.at n=0A236806
- T(n,k)=Number of (n+1)X(k+1) 0..2 arrays with the maximum plus the lower median minus the upper median minus the minimum of every 2X2 subblock equal.at n=10A236809
- T(n,k)=Number of (n+1)X(k+1) 0..2 arrays with the maximum plus the lower median minus the upper median minus the minimum of every 2X2 subblock equal.at n=14A236809
- Indices of record high values in A061836.at n=30A333533
- a(n) = a(n-1) + a(n-2) + gcd(a(n-1), n), a(1) = a(2) = 1.at n=19A360884
- a(n) = 12*n^2 + 4*n + 1.at n=38A381390