9879
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 33
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 13680
- Proper Divisor Sum (Aliquot Sum)
- 3801
- 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
- 6336
- Möbius Function
- -1
- Radical
- 9879
- 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
- 135
- 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
- n written in fractional base 10/9.at n=39A024664
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (F(2), F(3), F(4), ...), t = (primes).at n=19A025111
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 17 ones.at n=10A031785
- Number of partitions of n into parts not of form 4k+2, 20k, 20k+3 or 20k-3. Also number of partitions in which no odd part is repeated, with 1 part of size less than or equal to 2 and where differences between parts at distance 4 are greater than 1 when the smallest part is odd and greater than 2 when the smallest part is even.at n=53A036025
- Numbers whose base-5 representation contains exactly three 0's and two 4's.at n=27A045216
- Fourth column (r=3) of FS(3) staircase array A062745.at n=36A062748
- Beginning with 1, numbers such that the differences a(k)-a(k-1) are distinct and every concatenation n>1 is prime.at n=47A090504
- Numbers k that divide Lucas(k) + 1.at n=26A094398
- Odd numbers k that divide Lucas(k) + 1.at n=7A094399
- Numbers k such that 6*10^k-11 is prime.at n=16A102739
- a(n) = (10^k - n)(10^k + n), where k is the number of digits in n.at n=10A110397
- Starting numbers for which the RATS sequence has eventual period 14.at n=32A114615
- Start with 1015 and repeatedly reverse the digits and add 4 to get the next term.at n=83A117807
- Start with 1027 and repeatedly reverse the digits and add 16 to get the next term.at n=65A119455
- Numbers with rounded up arithmetic mean of digits = 9.at n=33A178369
- Concatenation of the decimal digits of Fibonacci(n) and the Fibonacci(n)-th digit of Pi.at n=16A201773
- a(n) = (6*n^2 + 7*n - 9 + 2*n^3)/12 - (-1)^n*(n+1)/4.at n=37A219527
- Number of blocks in a Steiner system S(2, 5, A228141(n+1)).at n=44A228142
- a(n) = Sum_{k=1, n} phi(k)*index(k, n), with phi(k) the Euler totient A000010(k) and index(k,n) the position of 1/k in the n-th row of the Farey sequence of order k, A049805(n,k).at n=39A244396
- Number of length n inversion sequences avoiding the patterns 110, 120, and 021.at n=9A279557