5581
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 5582
- Proper Divisor Sum (Aliquot Sum)
- 1
- 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
- 5580
- Möbius Function
- -1
- Radical
- 5581
- Omega Function (Ω)
- 1
- Little Omega Function (ω)
- 1
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
- 129
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 737
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Primes with 6 as smallest primitive root.at n=42A001125
- Centered 12-gonal numbers, or centered dodecagonal numbers: numbers of the form 6*k*(k-1) + 1.at n=30A003154
- Primes that remain prime through 2 iterations of function f(x) = 8x + 3.at n=43A023261
- T(n,n+1) + T(n,n+2) + ... + T(n,2n), T given by A027113.at n=7A027139
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 60 ones.at n=4A031828
- Lower prime of a difference of 10 between consecutive primes.at n=69A031928
- Value of D for incrementally largest values of minimal x satisfying Pell equation x^2-Dy^2=1.at n=28A033316
- a(n) = smallest prime == 1 (mod 4) such that a(n) is a square mod a(i), all i<n.at n=7A034700
- Number of partitions of n into parts not of the form 25k, 25k+2 or 25k-2. Also number of partitions with 1 part of size 1 and differences between parts at distance 11 are greater than 1.at n=35A036001
- Primes p such that (p+1)/2 and (p+2)/3 are also primes.at n=15A036570
- Used by Polya in calculating A000598.at n=14A036678
- Least k such that A033178(k)=n.at n=38A038004
- Primes of the form n*phi(n)+1 where phi(n) is the Euler function.at n=38A046062
- Third term of weak prime quintets: p(m-1)-p(m-2) < p(m)-p(m-1) < p(m+1)-p(m) < p(m+2)-p(m+1).at n=13A054825
- Primes p such that x^31 = 2 has no solution mod p.at n=22A059225
- Primes p such that x^5 == 2 (mod p) has five solutions.at n=36A059858
- Numbers p from A001125 such that 2*p-3 is prime.at n=10A063939
- Number of partitions of n into odious numbers (A000069).at n=48A067590
- Numbers k such that 1/(1/phi(k) + 1/phi(k+1) + 1/phi(k+2)) is an integer.at n=35A073543
- a(1) = 1 and then the smallest primes such that all a(k)-a(j) are distinct composite numbers.at n=35A079850