17561
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 18612
- Proper Divisor Sum (Aliquot Sum)
- 1051
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 16512
- Möbius Function
- 1
- Radical
- 17561
- 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
- 141
- 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
- Truncated tetrahedral numbers: a(n) = (1/6)*(n+1)*(23*n^2 + 19*n + 6).at n=16A005906
- Truncated octahedral numbers: 16*n^3 - 33*n^2 + 24*n - 6.at n=10A005910
- Starting positions of strings of three 9's in the decimal expansion of Pi.at n=13A083642
- Maximal troughs in decimal expansions of Pi: positions of troughs equal to 8.at n=20A105276
- Number of permutations of length n which avoid the patterns 2134, 3421, 4312.at n=14A116766
- Number of base 29 n-digit numbers with adjacent digits differing by four or less.at n=4A126524
- Floor(1/{(5+n^4)^(1/4)}), where {}=fractional part.at n=27A184629
- Number of transpose partition pairs of order n whose number of odd parts differ by numbers of the form 4*k + 2.at n=42A190101
- T(n,k)=Number of nXk 0..3 arrays with no element equal to one plus the sum of elements to its left or two plus the sum of the elements above it or zero plus the sum of the elements diagonally to its northwest, modulo 4.at n=46A240284
- Number of 2 X n 0..3 arrays with no element equal to one plus the sum of elements to its left or two plus the sum of the elements above it or zero plus the sum of the elements diagonally to its northwest, modulo 4.at n=8A240285
- Number of length 4+1 0..n arrays with the sum of the squares of adjacent differences multiplied by some arrangement of +-1 equal to zero.at n=11A250279
- Consider a number x. Take the sum of its digits. Repeat the process deleting the first addendum and adding the previous sum. The sequence lists the numbers that after some iterations reach the arithmetic derivative of x.at n=20A269312
- Indices n for which the partial sums of sin(k) (0 <= k <= n) reach a new minimum.at n=31A322288