1929
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
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 2576
- Proper Divisor Sum (Aliquot Sum)
- 647
- 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
- 1284
- Möbius Function
- 1
- Radical
- 1929
- 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
- 55
- 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
- Expansion of (Product_{j>=1} (1-(-x)^j) - 1)^9 in powers of x.at n=39A001487
- Coordination sequence T1 for Zeolite Code FER.at n=27A008106
- Coordination sequence T2 for Zeolite Code MTW.at n=29A008197
- Coefficients in expansion of e as Sum_{n>=1} a(n)/(n*n!*(n+1)!), as found by greedy algorithm.at n=42A011189
- Numbers k such that Fibonacci(k) == -2 (mod k).at n=30A023163
- [ Sum (s(j) - s(i))^2 ], 1 <= i < j <= n, where s(k) = 1 + 1/2 + ... + 1/k.at n=51A025216
- a(n) = (d(n)-r(n))/5, where d = A026043 and r is the periodic sequence with fundamental period (0,2,3,0,0).at n=27A026045
- a(n) = n^2 - 7.at n=41A028881
- Q(sqrt(n)) has class number 3.at n=38A029703
- Numbers whose base-10 representation has 2 fewer 0's than 9's.at n=34A031500
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 28.at n=21A031526
- Lower of pair of consecutive happy numbers.at n=43A035502
- Total number of different legs traversed by all loops of length 2n in A038515.at n=11A038516
- Numerators of continued fraction convergents to sqrt(968).at n=3A042872
- Numbers having two 9's in base 10.at n=38A043526
- Numbers k such that 2 and 9 occur juxtaposed in the base-10 representation of k but not of k+1.at n=38A044019
- Numbers n such that string 1,1 occurs in the base 8 representation of n but not of n-1.at n=30A044196
- Numbers n such that string 7,3 occurs in the base 9 representation of n but not of n-1.at n=25A044317
- Numbers n such that string 2,9 occurs in the base 10 representation of n but not of n-1.at n=21A044361
- Numbers n such that string 1,1 occurs in the base 8 representation of n but not of n+1.at n=30A044577