6537
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 8720
- Proper Divisor Sum (Aliquot Sum)
- 2183
- 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
- 4356
- Möbius Function
- 1
- Radical
- 6537
- Omega Function (Ω)
- 2
- 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
- 106
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 52.at n=38A031550
- Number of positive integers <= 2^n of form 3 x^2 + 6 y^2.at n=16A054163
- a(n) = 3^n mod n^3.at n=33A066607
- a(n) = (n-1)*(n-2)^3 - A003878(n-3), with a(1) = a(2) = 0 and a(3) = 2.at n=21A075681
- a(n) = 3*(2*n^2 + 1).at n=33A097803
- Numbers k such that 1 + (x + x^3 + x^5 + x^7 + ... + x^(2*k+1)) is irreducible over GF(2).at n=27A107220
- a(n) = 3^n - 3*n.at n=8A107583
- Semiprimes which are the sum of two pentagonal numbers (A000326) in exactly two different ways.at n=33A120536
- Number of maximal sum-free subsets of {1,2,...,n}.at n=31A121269
- Numerator of Sum[ Prime[k]^2, {k,1,n}] / Product[ Prime[k], {k,1,n}] = Numerator[ A024450[n] / A002110[n] ].at n=27A122136
- 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), (-1, 1, 0), (0, 0, 1), (1, 0, -1), (1, 0, 1)}.at n=7A150400
- Number of nondecreasing arrangements of n numbers in -3..3 with sum zero and sum of squares not greater than n*12/3.at n=22A183921
- G.f.: exp( Sum_{n>=1} (2*sigma(n^2) - sigma(n)^2) * x^n/n ).at n=16A195734
- Number of (n+1)X(n+1) 0..1 arrays with rows and columns of determinants of all 2X2 subblocks lexicographically nondecreasing.at n=2A204793
- Number of (n+1)X4 0..1 arrays with rows and columns of determinants of all 2X2 subblocks lexicographically nondecreasing.at n=2A204795
- T(n,k)=Number of (n+1)X(k+1) 0..1 arrays with rows and columns of determinants of all 2X2 subblocks lexicographically nondecreasing.at n=12A204800
- Number of palindromic partitions of n whose greatest part has multiplicity <= 3.at n=47A238786
- Rocket sequence 50: a(0)=50, a(n)=A073846(a(n-1)).at n=39A262149
- Sum of the 2nd smallest parts of all the partitions of n (2nd smallest part is defined to be 0 when the partition does not have at least 2 distinct parts).at n=24A265248
- G.f.: Sum_{k>=0} A000009(k)^2 * x^k / Sum_{k>=0} A000041(k) * x^k.at n=44A305350