9855
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
- 16
- Divisor Sum
- 17760
- Proper Divisor Sum (Aliquot Sum)
- 7905
- 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
- 5184
- Möbius Function
- 0
- Radical
- 1095
- Omega Function (Ω)
- 5
- 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
- 96
- 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
- no
- Odd
- yes
Appears in sequences
- Rhombic dodecahedral numbers: a(n) = n^4 - (n - 1)^4.at n=13A005917
- a(n) = n*(n^2 + 1)/2.at n=27A006003
- a(n) = n*(27*n + 1)/2.at n=27A022285
- Number of partitions of n into parts not of the form 17k, 17k+2 or 17k-2. Also number of partitions with 1 part of size 1 and differences between parts at distance 7 are greater than 1.at n=39A035963
- Numbers whose sum of the squares of divisors is also a square number.at n=11A046655
- Honaker's triangle problem: form a triangle with base of length n, all entries different, all row sums equal; a(n) gives minimal row sum.at n=39A047837
- a(n) = max_{r=1..n-1} ceiling(t(t(n)-t(r-1))/(n-r+1)), where t() = triangular numbers A000217.at n=39A047873
- The terms of A055235 (sums of two powers of 3) divided by 2.at n=48A073216
- Row sums of triangle A074135.at n=26A074132
- Sum of terms in each group in A074147.at n=26A074149
- Sums of terms of groups in A075621.at n=26A075625
- Triangle, read by rows, where the n-th row lists the (2n+1) coefficients of (1+2*x+3*x^2)^n.at n=44A084608
- Sum of the squares of the first n nonsquarefree numbers (A013929).at n=15A111732
- Numbers k such that k * (k+9) is the concatenation of a number m with itself.at n=7A116293
- Numbers k for which 2*k-1, 4*k-1, 8*k-1 and 16*k-1 are primes.at n=15A124494
- Numbers k such that k and k+5 are 5-almost primes.at n=40A124942
- Binomial transform of A107430.at n=60A126136
- RMS numbers: numbers n such that root mean square of divisors of n is an integer.at n=10A140480
- Triangle T(n, k) = Sum_{j=0..n} (2*n)!/((2*n-k-j)!*j!*k!), read by rows.at n=17A141723
- Primitive RMS numbers: RMS numbers which are not the product of two smaller RMS numbers.at n=7A141813