6561
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
- 9
- Divisor Sum
- 9841
- Proper Divisor Sum (Aliquot Sum)
- 3280
- 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
- 4374
- Möbius Function
- 0
- Radical
- 3
- Omega Function (Ω)
- 8
- Little Omega Function (ω)
- 1
Special
- Factorial
- no
- Catalan Number
- no
- Bell Number
- no
- Motzkin Number
- no
- Primorial
- no
Figurate Numbers
- Fibonacci Number
- no
- Triangular Number
- no
- Perfect Square
- yes
- 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
- 75
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- yes
- Achilles Number
- no
- Perfect Power
- yes
- Smooth Number
- yes
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Largest order of automorphism group of a tournament with n nodes.at n=17A000198
- Largest order of automorphism group of a tournament with n nodes.at n=19A000198
- Largest order of automorphism group of a tournament with n nodes.at n=18A000198
- Powers of 3: a(n) = 3^n.at n=8A000244
- Fourth powers: a(n) = n^4.at n=9A000583
- Expansion of bracket function.at n=16A000748
- a(n) = max{(n - i)*a(i) : i < n}; a(0) = 1.at n=24A000792
- Eighth powers: a(n) = n^8.at n=3A001016
- Powers of 9: a(n) = 9^n.at n=4A001019
- Glaisher's chi_8(n).at n=8A002607
- Numbers that are the sum of 3 positive 7th powers.at n=9A003370
- Numbers of the form 3^i*5^j with i, j >= 0.at n=29A003593
- Numbers of the form 3^i*7^j with i, j >= 0.at n=24A003594
- Numbers of the form 3^i*11^j.at n=20A003597
- Square array read by upwards antidiagonals: T(n,k) = n^k for n >= 0, k >= 0.at n=74A003992
- Array read by ascending antidiagonals: A(n, k) = k^n.at n=69A004248
- Numbers that are the sum of at most 2 nonzero 4th powers.at n=44A004831
- Numbers that are the sum of at most 3 positive 7th powers.at n=19A004865
- Numbers that are the sum of at most 4 positive 7th powers.at n=31A004866
- Numbers that are the sum of at most 5 positive 7th powers.at n=46A004867