17913
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
- 4
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 27328
- Proper Divisor Sum (Aliquot Sum)
- 9415
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 10224
- Möbius Function
- -1
- Radical
- 17913
- Omega Function (Ω)
- 3
- 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
- no
- Harshad Number
- yes
- Narcissistic Number
- no
- Collatz Steps
- 97
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- 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
- Seventh column (m=6) of convolution triangle A059594(n,m).at n=8A059595
- a(0) = 1; a(n) is obtained by incrementing each digit of a(n-1) by 8.at n=4A061748
- Triangle of generalized Stirling numbers of the first kind.at n=61A094645
- Expansion of e.g.f. (1 + y)^(1 + x).at n=61A105793
- Lucky numbers for which both the sum of the digits and the product of the digits is also a lucky number.at n=38A118559
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, 1, -1), (-1, 1, 1), (1, -1, 0), (1, 1, 1)}.at n=8A149573
- Number of binary strings of length n with no substrings equal to 0000 0110 or 1011.at n=14A164440
- a(n)=floor(3*n^2*(2+sqrt(3))).at n=39A172526
- Numbers that are the product of 3 distinct primes a,b and c, such that a+b+c, a^2+b^2+c^2 and a^3+b^3+c^3 are prime numbers.at n=21A176911
- Monotonic ordering of set S generated by these rules: if x and y are in S and x^2-y^2>0 then x^2-y^2 is in S, and 2 and 3 are in S.at n=17A192648
- L.g.f.: Sum_{n>=1} x^n/n * Sum_{k=0..n} binomial(n^2, k*(n-k))*x^k = Sum_{n>=1} a(n)*x^n/n.at n=5A207138
- a(n) is the number of digits in the decimal representation of the smallest power of n that contains nine consecutive identical digits.at n=35A217184
- Expansion of Product_{k>=1} (1 + x^(3*k-1))^(3*k-1) * (1 + x^(3*k-2))^(3*k-2).at n=24A262924
- Numbers k such that prime(k) is the hypotenuse of a Pythagorean triple where one leg is also prime.at n=23A342583
- Number T(n,k) of permutations of [n] having k cycles of the form (c1, c2, ..., c_m) where c1 = min_{i>=1} c_i and c_j = min_{i>=j} c_i or c_j = max_{i>=j} c_i; triangle T(n,k), n>=0, 0<=k<=n, read by rows.at n=50A344855
- Number of permutations of [n] having five cycles of the form (c1, c2, ..., c_m) where c1 = min_{i>=1} c_i and c_j = min_{i>=j} c_i or c_j = max_{i>=j} c_i.at n=4A346320
- Numbers k such that A383844(k) and A383844(k+1) are nonzero.at n=45A384310