11955
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 19152
- Proper Divisor Sum (Aliquot Sum)
- 7197
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6368
- Möbius Function
- -1
- Radical
- 11955
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 50
- 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 partitions of n into parts not of form 4k+2, 24k, 24k+7 or 24k-7. Also number of partitions in which no odd part is repeated, with at most 3 parts of size less than or equal to 2 and where differences between parts at distance 5 are greater than 1 when the smallest part is odd and greater than 2 when the smallest part is even.at n=49A036032
- Numbers n such that p = n^2 + 2, p+2 and p+6 are consecutive primes.at n=22A086380
- Smallest number k such that 2^n divides A066796(k) = Sum(i=1,k,binomial(2*i,i)).at n=12A126806
- a(1)=4. a(n) = a(n-1) + n, if a(n-1)+n is composite. Otherwise a(n) = a(n-1)*n.at n=19A175459
- Number of days after Mar 01 00 such that the date written in the format DD.MM.YY is palindromic.at n=11A210887
- Number of magic labelings with magic sum n of 2nd graph shown in link.at n=10A244870
- Number of length n+6 0..1 arrays with at most two downsteps in every 6 consecutive neighbor pairs.at n=7A256814
- Numbers k such that R_(k+2) + 6*10^k is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=21A256932
- Number of partitions of n having no perfect cube parts (n>=0).at n=46A264393
- Record values in A243145.at n=49A299112
- a(n) = Sum_{d|n} phi(d) * binomial(d+n/d-1, d).at n=44A338655
- Number of compositions with alternating parts weakly decreasing (or weakly increasing).at n=23A342528
- Number of free, holey, treelike polyominoes of n cells.at n=12A359522
- a(1) = 1, a(2) = 2; for n >= 3, a(n) = (n-1)^3 - a(n-1) - a(n-2).at n=32A361134
- Triangle read by rows: T(n, k) is the number of chains of length k in the poset of permutations of an n-set.at n=26A375835
- a(n) = Sum_{k=0..floor(n/3)} binomial(n+k-1,k) * binomial(n+2*k-1,n-3*k).at n=9A389378