2581
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 2700
- Proper Divisor Sum (Aliquot Sum)
- 119
- 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
- 2464
- Möbius Function
- 1
- Radical
- 2581
- 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
- 102
- 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
- Squares written in base 9.at n=43A002442
- Number of series-reduced 2-connected graphs with n nodes.at n=4A006289
- Coefficients of period polynomials.at n=22A006309
- a(n) = Fibonacci(n) - 3. Number of total preorders.at n=14A006327
- Coordination sequence T1 for Zeolite Code RSN.at n=33A009885
- Numbers k such that the continued fraction for sqrt(k) has period 7.at n=23A010338
- Powers of cube root of 2 rounded up.at n=34A017981
- Powers of cube root of 4 rounded up.at n=17A017987
- Pseudoprimes to base 88.at n=19A020216
- Fibonacci sequence beginning 0, 29.at n=11A022363
- a(n) = (prime(n)-1)*(prime(n)-5)/12.at n=38A030006
- Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted the two central terms are both 11.at n=1A031599
- Numbers with exactly five distinct base-7 digits.at n=16A031984
- "BHJ" (reversible, identity, labeled) transform of 2,1,1,1...at n=4A032077
- a(n) = floor(10000/sqrt(n)).at n=14A033433
- Trajectory of 1 under map n->13n+1 if n odd, n->n/2 if n even.at n=17A033964
- Fractional part of square root of a(n) starts with 8: first term of runs.at n=48A034114
- a(n) is root of smallest square starting with a string of n 'digit_6's.at n=2A034988
- Coordination sequence T3 for Zeolite Code STF.at n=34A038442
- Numerators of continued fraction convergents to sqrt(177).at n=4A041326