6690
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 16128
- Proper Divisor Sum (Aliquot Sum)
- 9438
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 1776
- Möbius Function
- 1
- Radical
- 6690
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 4
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
- 137
- 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
- yes
- Odd
- no
Appears in sequences
- Numbers that are the sum of 5 positive 7th powers.at n=16A003372
- Number of partitions of n with equal nonzero number of parts congruent to each of 0 and 1 (mod 4).at n=45A035546
- Numbers n such that there are equal numbers of 0's and 1's in first n digits of binary representation of Pi.at n=36A039624
- Numbers whose base-9 representation has exactly 5 runs.at n=35A043634
- Numbers whose base-4 representation contains exactly two 0's and four 2's.at n=20A045051
- Values of m such that N = (am+1)(bm+1)(cm+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,3.at n=29A064238
- a(n) = 1^n + 2^(n+1) + 3^(n+2).at n=7A066280
- a(1) = 1, a(n+1) is the smallest number such that there are n primes between a(n) and a(n+1) exclusive.at n=41A075342
- "The partial sums of the positions where T occurs in this sentence are one, eight, twentyfive, fortynine, eightythree, onehundredtwentysix, ..." (Variation of Aronson's sequence).at n=36A089613
- Numbers whose set of base 6 digits is {0,5}.at n=22A097252
- Shadow of Pi.at n=36A110621
- Numbers k such that the k-th triangular number plus the reverse of k gives a square.at n=7A113799
- Sum of consecutives primes p and q where p == 3 mod (10) and q == 7 mod (10).at n=43A138018
- Averages of twin prime pairs such that p1 * p2 + AverageTwinPrime is prime.at n=27A154667
- Averages of twin prime pairs which are a sum of averages of two consecutive twin prime pairs.at n=19A160916
- Square array read by antidiagonals (n >= 1, k >= 2): T(n,k) = b(n,k) + b(k-1,n+1), where b(n,k) = ((1 + sqrt(k))^n - (1 - sqrt(k))^n)/(2*sqrt(k)).at n=56A173739
- Square array read by antidiagonals (n >= 1, k >= 2): T(n,k) = b(n,k) + b(k-1,n+1), where b(n,k) = ((1 + sqrt(k))^n - (1 - sqrt(k))^n)/(2*sqrt(k)).at n=64A173739
- Number of (n+1) X 5 0..1 arrays with column and row pair sums b(i,j)=a(i,j)+a(i,j-1) and c(i,j)=a(i,j)+a(i-1,j) nondecreasing in column and row directions, respectively.at n=10A204647
- Number of terms of 2^j + 3^k <= 10^n.at n=30A219835
- Number of nX5 0..2 arrays with no element equal to zero plus the sum of elements to its left or zero plus the sum of elements above it or zero plus the sum of the elements diagonally to its northwest, modulo 3.at n=11A240036