4945
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 22
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 6336
- Proper Divisor Sum (Aliquot Sum)
- 1391
- 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
- 3696
- Möbius Function
- -1
- Radical
- 4945
- 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
- 121
- 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
- Number of squares on infinite chessboard at <= n knight's moves from a fixed square.at n=19A018836
- Pseudoprimes to base 93.at n=34A020221
- Closed 3-dimensional ball numbers (version 1): a(n)= number of integer points (i,j,k) contained in a closed ball of diameter n, centered at (0,0,0).at n=21A053591
- Open 3-dimensional ball numbers (version 1): a(n) is the number of integer points (i,j,k) contained in an open ball of diameter n, centered at (0,0,0).at n=21A053592
- Triangular array giving number of labeled graphs on n unisolated nodes and k=0...n*(n-1)/2 edges.at n=35A054548
- Number of connected labeled graphs with n nodes and n+3 edges.at n=5A061542
- Triangular array T(n,k) giving number of connected graphs with n labeled nodes and k edges (n >= 1, 0 <= k <= n(n-1)/2).at n=34A062734
- a(n) = A064842(n)/2.at n=30A064843
- phi(n) + phi(reverse(n)) = sigma(n).at n=5A071846
- Sum of the first n primes whose indices are primes.at n=24A083186
- Numbers n such that numerator(Bernoulli(2*n)/(2*n)) is different from numerator(Bernoulli(2*n)/(2*n*(2*n+1))).at n=17A090177
- Numbers such that the sum of the digits of floor(phi^n) is also the sum of the digits of the n-th Fibonacci number (in base 10), where phi is the golden ratio.at n=41A111366
- Triangle P, read by rows, such that P^3 transforms column k of P into column k+1 of P, so that column k of P equals column 0 of P^(3*k+1), where P^3 denotes the matrix cube of P.at n=24A113370
- Column 3 of triangle A113370, also equals column 0 of A113370^10.at n=3A113373
- Triangle, read by rows, given by the product R^2*Q^-1 = Q^3*P^-2 using triangular matrices P=A113370, Q=A113381, R=A113389.at n=17A114150
- a(n) = Sum_{k=1..phi(n)-1} t(n,k)*t(n,k+1), where t(n,k) is the k-th positive integer which is coprime to n and phi(n) is the number of positive integers which are <= n and are coprime to n.at n=31A119584
- Where records occur in A118878.at n=11A119904
- Triangular array T(n,k) giving number of connected graphs with n labeled nodes and k edges (n >= 1, n-1 <= k <= n(n-1)/2).at n=19A123527
- Numbers k such that 1 + k + k^3 + k^5 + k^7 + k^9 + k^11 + k^13 + k^15 + k^17 + k^19 + k^21 + k^23 + k^25 + k^27 + k^29 + k^31 + k^33 + k^35 + k^37 + k^39 + k^41 + k^43 is prime.at n=41A124200
- a(n) = (p(n)*p(n+2) - p(n+1))/2, where p(n) is the n-th odd prime.at n=23A152531