2919
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
- 8
- Divisor Sum
- 4480
- Proper Divisor Sum (Aliquot Sum)
- 1561
- 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
- 1656
- Möbius Function
- -1
- Radical
- 2919
- 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
- yes
- Harshad Number
- yes
- Narcissistic Number
- no
- Collatz Steps
- 216
- 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
- Related to population of numbers of form x^2 + y^2.at n=13A000709
- Numbers that are the sum of 7 positive 6th powers.at n=26A003363
- In the '3x+1' problem, these values for the starting value set new records for number of steps to reach 1.at n=23A006877
- Coordination sequence T4 for Zeolite Code AFR.at n=41A008022
- Coordination sequence T1 for Zeolite Code GOO.at n=37A008111
- Coordination sequence T1 for Zeolite Code JBW.at n=36A008121
- Coordination sequence T1 for Zeolite Code MEP.at n=32A008157
- Coordination sequence T2 for Keatite.at n=30A009845
- Coordination sequence T2 for Zeolite Code -WEN.at n=39A009863
- Quadruples of different integers from [ 1,n ] with no global factor.at n=17A015622
- Quadruples of different integers from [ 2,n ] with no global factor.at n=17A015627
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = (odd natural numbers), t = A000201 (lower Wythoff sequence).at n=21A024599
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (odd natural numbers), t = A000201 (lower Wythoff sequence).at n=20A025113
- Sum of the numbers between the two n's in A026362.at n=28A026365
- Number of partitions of n into an even number of parts, the least being 4; also, a(n+4) = number of partitions of n into an odd number of parts, each >=4.at n=58A027196
- 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 36.at n=11A031534
- Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 36.at n=2A031714
- In the '3x+1' problem, these values for the starting value set new records for number of steps to reach 1.at n=17A033958
- Number of partitions of n into parts 5k+1 or 5k+2.at n=51A035371
- Number of partitions of n such that cn(3,5) < cn(0,5) = cn(1,5) <= cn(2,5) = cn(4,5).at n=70A036875