6724
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 9
- Divisor Sum
- 12061
- Proper Divisor Sum (Aliquot Sum)
- 5337
- 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
- 3280
- Möbius Function
- 0
- Radical
- 82
- 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
- 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
- 44
- 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
- yes
- Achilles Number
- no
- Perfect Power
- yes
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- yes
- Odd
- no
Appears in sequences
- a(n) = (prime(n) - 1)^2.at n=22A005722
- a(0)=1, a(1)=9, a(n) = sum_{k=0}^{k=n-1} 9^k a(k).at n=3A015497
- Even squares: a(n) = (2*n)^2.at n=41A016742
- a(n) = (3*n+1)^2.at n=27A016778
- a(n) = (4n + 2)^2.at n=20A016826
- a(n) = (5*n + 2)^2.at n=16A016874
- a(n) = (6*n + 4)^2.at n=13A016958
- a(n) = (7*n + 5)^2.at n=11A017042
- a(n) = (8*n + 2)^2.at n=10A017090
- a(n) = (9*n + 1)^2.at n=9A017174
- a(n) = (10*n + 2)^2.at n=8A017294
- a(n) = (11*n + 5)^2.at n=7A017450
- a(n) = (12*n+10)^2.at n=6A017642
- Numbers k that are the sum of m nonzero squares for all 1 <= m <= k - 14.at n=28A018820
- Sum of digits in n-th term of A022470.at n=28A022475
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = (Lucas numbers), t = (primes).at n=17A024478
- a(n) = least m such that if r and s in {1/1, 1/3, 1/5, ..., 1/(2n-1)} satisfy r < s, then r < k/m < (k+1)/m < s for some integer k.at n=44A024834
- Duplicate of A024478.at n=17A025090
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (Lucas numbers), t = (primes).at n=16A025098
- Squares which are palindromes in base 3.at n=11A029985