6989
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 32
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 7260
- Proper Divisor Sum (Aliquot Sum)
- 271
- 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
- 6720
- Möbius Function
- 1
- Radical
- 6989
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 150
- 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 19*2^k - 1 is prime.at n=22A001775
- a(n) = 10000*log_10(n) rounded down.at n=4A004228
- Number of walks on cubic lattice.at n=28A005570
- Expansion of g.f. 1/((1-2*x)*(1-11*x)*(1-12*x)).at n=3A016633
- Numbers whose concatenation of prime factors (with multiplicity) is a square.at n=20A038693
- Number of irreducible representations of symmetric group S_n for which every matrix has determinant 1.at n=31A045923
- Sum of digits = 8 times number of digits.at n=16A061425
- Semiprimes p1*p2 such that p2 mod p1 = 9, with p2 > p1.at n=33A064907
- Indices of primes in sequence defined by A(0) = 21, A(n) = 10*A(n-1) + 61 for n > 0.at n=8A101966
- Numerators of first difference of squares of harmonic numbers.at n=8A103932
- Numerator of Sum_{k=1..n} (-1)^(k+1)/prime(k)^2.at n=3A136368
- a(n) = 25*n^2 - 14*n + 2.at n=17A154357
- Positive numbers y such that y^2 is of the form x^2+(x+241)^2 with integer x.at n=7A159565
- Numerator of the Harary number for the cycle graph C_n.at n=17A160046
- Numbers n such that the digits of sigma(n) are exactly the same (albeit in different order) as the digits of phi(n), in base 10.at n=14A175795
- Number of (n+2) X 3 binary arrays with each 3 X 3 subblock having rows and columns in lexicographically nondecreasing order.at n=24A184540
- G.f.: Sum_{n>=0} n! * (1+n*x)^n * x^n / Product_{k=1..n} (1 + k*x + n*k*x^2).at n=7A185310
- a(n) = n*prime(prime(n)) - prime(n).at n=19A230285
- Semiprimes with strictly increasing product of digits.at n=43A246569
- Number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 611", based on the 5-celled von Neumann neighborhood.at n=45A273212