5621
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 14
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 7104
- Proper Divisor Sum (Aliquot Sum)
- 1483
- 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
- 4320
- Möbius Function
- -1
- Radical
- 5621
- 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
- 85
- 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
- a(n) = (6*n+1)*(6*n+5).at n=12A001513
- a(n) = (4*n+1)*(4*n+5).at n=18A003185
- a(n) = number of length-n sequences s with s[1]=1, s[2]=1, s[k-1] <=s[k] <= s[k-2]+s[k-1] (s is called a sub-Fibonacci sequence of length n).at n=7A005269
- a(n) = floor( n*(n-1)*(n-2)/28 ).at n=55A011910
- Pseudoprimes to base 27.at n=40A020155
- Pisot sequence T(4,10), a(n) = floor(a(n-1)^2/a(n-2)).at n=8A020748
- a(n) = floor(floor(S3)/floor(S1)), where S3 and S1 are, respectively, the 3rd and first elementary symmetric functions of {sqrt(k), k = 1,2,...,n}.at n=40A025200
- Numbers k such that 53*2^k+1 is prime.at n=14A032376
- Numerators of continued fraction convergents to sqrt(703).at n=5A042352
- Numbers whose base-5 representation contains exactly two 1's and three 4's.at n=33A045258
- a(n) = Sum{a(k): k=0,1,2,...,n-4,n-2,n-1}; a(n-3) is not a summand; initial terms are 1,2,4.at n=14A049870
- Trajectory of 23 under map that sends x to 3x - sigma(x), where sigma(x) is the sum of the divisors of x.at n=10A058545
- a(n) = (2*n+5)*(2*n+1).at n=36A078371
- Numbers k such that k*primorial(2473)-1 is prime.at n=44A087832
- Number of squares on infinite quarter chessboard at <=n knight moves from the corner.at n=40A098500
- Least multiple of prime(n) ending in digits of n.at n=17A114012
- Number of peak-avoiding compositions with positive parts.at n=17A128768
- Number of n X n binary matrices, symmetric under 180 degree rotation, with no more than 3 ones in any 2 X 2 subblock.at n=5A141514
- Second trisection of A061037.at n=24A142599
- a(n) = 100*n^2 + 100*n + 21.at n=7A152161