6129
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 9120
- Proper Divisor Sum (Aliquot Sum)
- 2991
- 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
- 4068
- Möbius Function
- 0
- Radical
- 681
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 2
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
- 49
- 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
- a(n) = Sum_{k=1..n-1} k^2*sigma(k)*sigma(n-k).at n=8A000477
- Expansion of e.g.f.: exp(sinh(x)*cos(x)).at n=10A009228
- Powers of fifth root of 13 rounded down.at n=17A018150
- Powers of fifth root of 13 rounded to nearest integer.at n=17A018151
- Numbers k such that the continued fraction for sqrt(k) has period 76.at n=9A020415
- Decimal part of cube root of a(n) starts with 3: first term of runs.at n=16A034129
- Numbers whose base-5 representation contains exactly two 0's and three 4's.at n=13A045213
- a(n) = a(n-1) + a(m) for n >= 4, where m = 2*n - 3 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = a(2) = 1 and a(3) = 2.at n=32A050028
- a(n) = a(n-1) + a(m) for n >= 4, where m = 2*n - 3 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1 and a(2) = a(3) = 2.at n=32A050044
- a(n) = a(n-1) + a(m) for n >= 4, where m = 2*n - 3 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1, a(2) = 3, and a(3) = 2.at n=32A050060
- Least positive integers, all distinct, that satisfy sum(n>0,1/a(n)^z)=0, where z=(60+I*11)/61.at n=10A084804
- a(n) = 6*2^n - n - 5.at n=10A101945
- The first 8 values are predefined, the remaining set to a(n) = 48*prime(n)+n+2.at n=30A129025
- Partial sums of A130237.at n=39A130238
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 1), (0, 0, 1), (0, 1, 1), (1, 1, -1), (1, 1, 1)}.at n=6A151225
- Sum of distinct residues of all factorials mod prime(n).at n=33A210185
- Floor(-1/n + 1/log((2n+1)/(2n-1))).at n=7A227512
- Numbers k such that the decimal number 1k is a square.at n=38A272671
- Terms of A272671 which are not a power of 100 times an earlier term of A272671.at n=35A272684
- Number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 809", based on the 5-celled von Neumann neighborhood.at n=44A273610