17545
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 22
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 23940
- Proper Divisor Sum (Aliquot Sum)
- 6395
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 12320
- Möbius Function
- 0
- Radical
- 1595
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 216
- 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=1..n-1} k^2*sigma(k)*sigma(n-k).at n=10A000477
- a(n) = n*(n+1)*(4*n+5)/6.at n=29A016061
- Length of hypotenuse squared in right triangle formed by a palindromic spiral plotted in Cartesian coordinates.at n=17A048871
- Total number of prime power parts in all partitions of n.at n=27A073335
- a(n) = 15*n^2 + 6*n + 1.at n=34A080861
- a(n) = n!*b(n), where b(n) = (1 + n - n^2)*b(n-2)/(n*(n-1)), b(0) = b(1) = 1.at n=8A123025
- 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, 0), (1, -1, 1), (1, 0, 0)}.at n=10A148229
- 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), (0, 1, 0), (1, 0, 0), (1, 1, 1)}.at n=7A151117
- Volume of torus (rounded down) with major radius = n and minor radius = n/3.at n=19A228641
- Numbers whose binary representation traces a nonselfcrossing circuit in honeycomb lattice when its bits (from the least to the second most significant bit) are interpreted as directions to proceed at each vertex. (The most significant 1-bit is ignored).at n=50A255571
- Those terms of A255571 whose every A080541/A080542-rotation is also a term of A255571.at n=25A258001
- Expansion of e.g.f. 1/(1 - x - x/((1 - x^2)^(1/2) - x/((1 - x^3)^(1/3) - x/((1 - x^4)^(1/4) - ...)))), a continued fraction.at n=5A295836
- Number of nX4 0..1 arrays with every element equal to 1, 2, 4 or 6 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.at n=8A300765
- Odd composite integers m such that A087130(m) == 5 (mod m).at n=30A335671
- Numbers whose square can be represented in exactly two ways as the sum of a positive square and a positive fourth power.at n=39A345700