1689
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 24
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 2256
- Proper Divisor Sum (Aliquot Sum)
- 567
- 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
- 1124
- Möbius Function
- 1
- Radical
- 1689
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 34
- 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
- Harary-Read numbers: restricted hexagonal polyominoes (cata-polyhexes) with n cells.at n=9A002216
- Scaled sums of odd reciprocals: a(n) = (2*n + 1)!!*(Sum_{k=0..n} 1/(2*k + 1)).at n=4A004041
- Sequence and first differences (A030124) together list all positive numbers exactly once.at n=52A005228
- Number of 2-dimensional directed compact animals of size n.at n=8A006801
- Irregular triangle read by rows: Whitney numbers of the second kind a(n,k), n >= 1, k >= 0, for the star poset.at n=33A007799
- Number of non-Abelian metacyclic groups of order p^n (p odd).at n=45A007983
- Coordination sequence T1 for Zeolite Code GME and AFX.at n=31A008110
- Coordination sequence T3 for Zeolite Code VET.at n=25A009904
- First n elements of Thue-Morse sequence A010060 read as a binary number.at n=11A019300
- Numbers k such that the continued fraction for sqrt(k) has period 48.at n=6A020387
- Numbers k such that Fibonacci(k) == -2 (mod k).at n=27A023163
- Convolution of natural numbers >= 2 and natural numbers >= 3.at n=17A023545
- 4th elementary symmetric function of the first n+3 odd positive integers.at n=1A024198
- Numbers that are the sum of 3 nonzero squares in exactly 10 ways.at n=38A025330
- Index of 5^n within the sequence of the numbers of the form 4^i*5^j.at n=53A025706
- Index of 8^n within the sequence of the numbers of the form 6^i*8^j.at n=53A025730
- Sum{T(n,k)}, k = 0,1,...,n, where T is the array defined in A024996.at n=8A026080
- Triangle of coefficients in expansion of (x+1)*(x+3)*...*(x + 2n - 1) in rising powers of x.at n=16A028338
- Clog sequence in base 2. Right to left concatenation of n,int(log_2(n)),int(log_2(int(log_2(n)))),... in base 2.at n=24A028423
- Numbers having period-14 7-digitized sequences.at n=31A031205