7668
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 27
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 24
- Divisor Sum
- 20160
- Proper Divisor Sum (Aliquot Sum)
- 12492
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 2520
- Möbius Function
- 0
- Radical
- 426
- Omega Function (Ω)
- 6
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 57
- 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
- yes
- Odd
- no
Appears in sequences
- a(n) = n*(21*n + 1)/2.at n=27A022279
- Expansion of (1+x^2-x^3)/(1-x)^4.at n=33A027378
- Numbers k such that 10^k + 3 is prime.at n=16A049054
- Numbers k such that phi(k)*d(k) is a multiple of sigma(k), where d(k) is the number of divisors of k.at n=30A050934
- Numbers k such that sigma(k) = 2*usigma(k).at n=21A063880
- Numbers k such that ud(k)*phi(k) = sigma(k), ud(k) = A034444.at n=8A063903
- a(n) = (9*n^2 + 5*n + 2)/2.at n=41A064225
- Numbers k such that gcd(k, reverse(k)) = 27 = 3^3, where reverse(x) = A004086(x).at n=20A072016
- 3 times hexagonal numbers: a(n) = 3*n*(2*n-1).at n=36A094159
- Number of partitions of n-set in which number of blocks of size 2k is even (or zero) for every k.at n=9A102759
- Numbers n such that sigma(n) = 8*phi(n).at n=4A104901
- Triangle of numbers, called Y(1,2), related to generalized Catalan numbers A062992(n) = C(2;n+1) = A064062(n+1).at n=25A115195
- Number of 2-cell columns in all deco polyominoes of height n. A deco polyomino is a directed column-convex polyomino in which the height, measured along the diagonal, is attained only in the last column.at n=6A121639
- Numbers n such that n-th and (n+1)-th primes are in A125146.at n=5A128120
- 9 times pentagonal numbers: 9*n*(3*n-1)/2.at n=24A152996
- 2-comma numbers: n occurs in the sequence S[k+1] = S[k] + 10*last_digit(S[k-1]) + first_digit(S[k]) for two different splittings n=concat(S[0],S[1]).at n=39A166512
- Expansion of f(x)^12 in powers of x where f() is a Ramanujan theta function.at n=29A209676
- The number of different lattice paths from (0,0) to (2n,0) using steps of S={(i,i) or (i,-i): i=1,2,...,n} with j flaws(j=1,2,...,n-1), where the j flaws is the sum of lengths of down steps below the x-axis. (For down steps that are partly above and partly below the x-axis we just count the part below the x-axis.) This number is independent of the number of flaws.at n=6A210474
- The number of single edges on the boundary of ordered trees with n edges.at n=9A228180
- 10-step Fibonacci sequence starting with 0,0,0,1,0,0,0,0,0,0.at n=23A251764