17685
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 27
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 31680
- Proper Divisor Sum (Aliquot Sum)
- 13995
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 9360
- Möbius Function
- 0
- Radical
- 1965
- Omega Function (Ω)
- 5
- 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
- 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
- (n-th Fibonacci number that is not 1) - (n-th number that is 1 or not a Fibonacci number).at n=19A014242
- Sum of the prime factors of k equals half the sum of the prime factors of k + 1.at n=13A074213
- a(n) = (4*n+3)*(4*n+7).at n=32A085027
- Recurrence sequence based on positions of digits in decimal places of Catalan's constant, G (often also called K).at n=8A098322
- Third trisection of A061037.at n=43A142600
- a(n) = (8*n+3)*(8*n+7).at n=16A146301
- 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, 1), (-1, 1, 0), (0, 0, -1), (1, -1, 1), (1, 0, 1)}.at n=9A148821
- Half the number of length n integer sequences with sum zero and sum of squares 200.at n=4A157542
- a(n) = n*(n+1)*(5*n^2 - n - 3)/2.at n=9A172118
- Trisection A061037(3*n-2) of the Balmer spectrum numerators extended to negative indices.at n=45A174325
- Quintisection A061037(5*n-2).at n=27A174850
- Number of subsets of {1..n} (including empty set) such that the pairwise sums of distinct elements are all distinct.at n=20A196723
- Deficient numbers n having a companion m > n such that sigma(n)/n = sigma(m)/m.at n=31A212608
- Number of partitions of n such that the number of odd parts is not a part and the number of even parts is not a part.at n=41A240579
- Number of factorizations of m^n into exactly eight factors, where m is a product of two distinct primes.at n=9A277244
- Expansion of Sum_{p prime, i>=1} x^(p^i) / (1 - Sum_{p prime, j>=1} x^(p^j))^2.at n=19A281852
- Numbers k such that k![6]-2 is prime, where k![6] = A085158 (k) = sextuple factorial.at n=37A283485