1839
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
- 2456
- Proper Divisor Sum (Aliquot Sum)
- 617
- 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
- 1224
- Möbius Function
- 1
- Radical
- 1839
- 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
- 161
- 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
- Numbers k such that Fibonacci(k) == -2 (mod k).at n=29A023163
- 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=16A031526
- Lucky numbers with size of gaps equal to 18 (lower terms).at n=11A031900
- a(1) = 2; a(n) is smallest number >= a(n-1) such that the juxtaposition a(1)a(2)...a(n) is a prime.at n=25A033679
- Number of partitions of n with equal nonzero number of parts congruent to each of 0 and 2 (mod 4).at n=35A035547
- Number of 4-ary rooted trees with n nodes and height exactly 4.at n=16A036628
- Number of partitions of n such that cn(0,5) = cn(2,5) <= cn(3,5) = cn(4,5) <= cn(1,5).at n=46A036846
- Growth function (or coordination sequence) of the infinite cubic graph corresponding to the srs net (a(n) = number of nodes at distance n from a fixed node).at n=37A038620
- Denominators of continued fraction convergents to sqrt(490).at n=6A041935
- Numbers k such that 3 and 9 occur juxtaposed in the base-10 representation of k but not of k-1.at n=36A043245
- Numbers k such that 3 and 8 occur juxtaposed in the base-10 representation of k but not of k+1.at n=36A044024
- Numbers k such that 3 and 9 occur juxtaposed in the base-10 representation of k but not of k+1.at n=36A044025
- Numbers k such that string 3,5 occurs in the base 7 representation of k but not of k-1.at n=42A044164
- Numbers n such that string 5,7 occurs in the base 8 representation of n but not of n-1.at n=31A044234
- Numbers k such that the string 6,3 occurs in the base 9 representation of k but not of k-1.at n=24A044308
- Numbers n such that string 3,9 occurs in the base 10 representation of n but not of n-1.at n=20A044371
- Numbers n such that string 4,5 occurs in the base 8 representation of n but not of n+1.at n=32A044605
- Numbers n such that string 5,7 occurs in the base 8 representation of n but not of n+1.at n=31A044615
- Numbers n such that string 6,3 occurs in the base 9 representation of n but not of n+1.at n=24A044689
- Numbers n such that string 3,9 occurs in the base 10 representation of n but not of n+1.at n=20A044752