9145
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 11520
- Proper Divisor Sum (Aliquot Sum)
- 2375
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6960
- Möbius Function
- -1
- Radical
- 9145
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 65
- 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
- Expansion of 1/((1-8*x)*(1-10*x)*(1-11*x)).at n=3A020979
- a(n) = n*(19*n + 1)/2.at n=31A022277
- Truncated triangular pyramid numbers: a(n) = Sum_{k=9..n} (k*(k+1)/2 - 45).at n=30A051943
- Triangle T(n,k) is the number of restricted growth strings (RGS) of set partitions of {1..n} that have an increase at index k (1<=k<n).at n=34A056861
- Non-balanced numbers in A015765.at n=39A074868
- Triangle read by rows: T(n,k) (n,k>=0) = number of peakless Motzkin paths of length n having k valleys (i.e., (1,-1) followed by (1,1)) at level zero (can be easily translated into RNA secondary structure terminology).at n=29A110333
- Number of peakless Motzkin paths of length n having no valleys (i.e., (1,-1) followed by (1,1)) at level zero (can be easily translated into RNA secondary structure terminology).at n=14A110334
- Numbers n such that p(9n) is prime, where p(n) is the number of partitions of n.at n=17A114169
- Start with 1027 and repeatedly reverse the digits and add 16 to get the next term.at n=36A119455
- Ulam's spiral (NNE spoke).at n=24A143861
- Number of distinct solutions of sum{i=1..4}(x(2i-1)*x(2i)) = 1 (mod n), with x() only in 1..n-1.at n=8A180786
- Floor[1/{(3+n^4)^(1/4)}], where {}=fractional part.at n=18A184538
- Values of n such that L(10) and N(10) are both prime, where L(k) = (n^2+n+1)*2^(2*k) + (2*n+1)*2^k + 1, N(k) = (n^2+n+1)*2^k + n.at n=33A227448
- a(n) = greatest k such that A155043(k+A262509(n)) < A155043(A262509(n)).at n=59A262909
- Increasing sequence a(n)>a(n-1) where a(n)=smallest integer not yet in the sequence with no digits shared with the previous term a(n-1), no repeated digits, and no 0-digit allowed.at n=25A290386
- Increasing sequence where a(n) is the smallest integer not yet in the sequence with no digits shared with the term a(n-2), no repeated digits, and no 0-digit allowed.at n=41A290387
- Number of inequivalent ways of placing 2 nonattacking rooks on n X n board up to rotations and reflections of the board.at n=19A307304
- Triangle read by rows: T(m,n) is the label of the ending square of an (m,n)-leaper (a generalization of a chess knight) when it can no longer move, starting on a board with squares spirally numbered, starting at 1; 1 <= n < m. Each move is to the lowest-numbered unvisited square.at n=41A323750
- Sum of the largest parts of the partitions of n into 9 squarefree parts.at n=40A326532
- Number of ON cells at n-th generation in the "Ulam-Warburton and Friedkin Replicator" hybrid two-dimensional cellular automaton.at n=51A335796