6969
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 30
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 9792
- Proper Divisor Sum (Aliquot Sum)
- 2823
- 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
- 4400
- Möbius Function
- -1
- Radical
- 6969
- 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
- 57
- 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
- Strobogrammatic numbers: the same upside down.at n=28A000787
- Pseudoprimes to base 91.at n=42A020219
- Least k such that the first k terms of the Kolakoski sequence (A000002) contain n more 2's than 1's.at n=6A025503
- Numerators of continued fraction convergents to sqrt(872).at n=5A042684
- a(1) = 6; a(n) is smallest number >= a(n-1) such that the juxtaposition a(1)a(2)...a(n) is a prime.at n=42A046256
- 1/3-Smith numbers.at n=0A050225
- Numbers that are unchanged when turned upside down, when written in a font in which 7 looks like upside-down 2.at n=47A051791
- Let Py(n)=A000330(n)=n-th square pyramidal number. Consider all integer triples (i,j,k), j >= k>0, with Py(i)=Py(j)+Py(k), ordered by increasing i; sequence gives k values.at n=40A053721
- Numbers n such that nextprime(n^3)-prevprime(n^3) = 4.at n=33A090121
- Numbers that look the same when rotated by 180 degrees, using only digits 0, 6 and 9.at n=7A111065
- Numbers that look the same when printed upside down.at n=14A111156
- 3-almost primes with semiprime digits (digits 4, 6, 9 only).at n=20A111494
- Odd integers that do not generate monotonically decreasing infinitary aliquot sequences.at n=16A127667
- Triangle T(n,k), read by rows n>=0 with terms k=1..3^n, where row n lists the coefficients in the n-th iteration of (x+x^2+x^3).at n=29A166880
- Numbers that are the same upside down (using only digits 0, 1, 6 and 9).at n=18A169731
- Numbers k for which 5*k-4, 5*k-2, 5*k+2, and 5*k+4 are primes.at n=22A178082
- Numbers k such that (k^3 - 2, k^3 + 2) is a pair of cousin primes (see A178227).at n=32A178228
- Number of increasing sequences of n integers x(1),...,x(n) with values in 1..3*n such that x(j) divides x(k) if j divides k.at n=14A180385
- Smallest (1/n)-Smith number.at n=2A195373
- Numbers without digit 0 or 5 whose "waterfall sequence" ends in 0,0,0,...at n=30A210614