6205
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 7992
- Proper Divisor Sum (Aliquot Sum)
- 1787
- 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
- 4608
- Möbius Function
- -1
- Radical
- 6205
- 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
- 155
- 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
- Expansion of 1/(1 - x^10 - x^11 - x^12 - x^13 - x^14 - x^15 - x^16).at n=73A017892
- Pseudoprimes to base 72.at n=26A020200
- Numbers that are the sum of 2 nonzero squares in exactly 4 ways.at n=29A025287
- Numbers that are the sum of 2 nonzero squares in 4 or more ways.at n=30A025295
- Numbers that are the sum of 2 distinct nonzero squares in exactly 4 ways.at n=29A025305
- Numbers that are the sum of 2 distinct nonzero squares in 4 or more ways.at n=30A025314
- Triangle read by rows of numbers of permutations eliminating just card k out of n in game of Mousetrap.at n=42A028306
- Denominators of continued fraction convergents to sqrt(461).at n=11A041879
- Numbers k such that the initial k digits in decimal portion of Pi form a prime number.at n=4A047658
- Number of colors that can be mixed with up to n units of yellow, blue, red.at n=34A048134
- Every 25th Fibocyclotomic number.at n=1A051259
- 13-gonal (or tridecagonal) numbers: a(n) = n*(11*n - 9)/2.at n=34A051865
- Numbers k such that 3*2^k - 7 is prime.at n=31A059747
- Relative class number h- of cyclotomic field Q(zeta_n) where n runs through positive integers not congruent to 2 (mod 4) [A042965, but omitting the initial 0].at n=63A061494
- Expansion of 1/((1-x)^2*(1-x^2)^2*(1-x^3)*(1-x^4)^2*(1-x^5)).at n=21A069957
- Number of permutations p of {1,2,...,n} such that |p(i)-i| != 1 for all i.at n=8A078480
- Numbers m that are the hypotenuse of exactly 13 distinct integer-sided right triangles, i.e., m^2 can be written as a sum of two squares in 13 ways.at n=23A097102
- Numbers k such that the continued fraction of (1 + sqrt(k))/2 has period 9.at n=40A143577
- 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, 0, 0), (0, 0, 1), (1, -1, 1), (1, 1, -1)}.at n=9A148363
- a(0)=4; a(n)=n^2+a(n-1) for n>0.at n=26A153058