6581
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 6582
- 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
- 6580
- Möbius Function
- -1
- Radical
- 6581
- 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
- 137
- 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
- yes
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 852
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Primes p such that the multiplicative order of 2 modulo p is (p-1)/5.at n=20A001135
- Smallest prime p such that first n primes (p_1=2, ..., p_n) are quintic residues mod p.at n=2A002226
- Numbers k such that 6!*(2*k-7)!/(k!*(k-1)!) is an integer.at n=7A004786
- Numbers k such that 7!*(2k-8)!/(k!*(k-1)!) is an integer.at n=8A004787
- f-vectors for simplicial complexes of dimension at most 1 (graphs) on at most n-1 vertices.at n=34A011826
- Discriminants of quintic fields with 4 complex conjugates.at n=37A023685
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 40 ones.at n=28A031808
- Lower prime of a difference of 18 between consecutive primes.at n=25A031936
- Least number of Sort-then-add persistence n.at n=33A033863
- Least number of Sort-then-add persistence n.at n=33A033908
- Position reached by frog in A038029. A038026(A038029(n)).at n=35A038031
- Least prime in A031936 (lesser of 18-twins) whose distance to the next 18-twin is 2*n.at n=10A052358
- Primes p whose period of reciprocal equals (p-1)/5.at n=15A056210
- Primes p such that x^47 = 2 has no solution mod p.at n=20A059257
- Primes with 14 as smallest positive primitive root.at n=6A061327
- Primes such that prime(p) +- pi(p) are simultaneously prime.at n=13A065117
- Numbers n such that n and the n-th prime have the same digits.at n=13A074350
- Difference between the arithmetic mean of the neighbors of the terms and the term itself follows the pattern 0,1,2,3,4,5,...at n=28A086514
- Solution to the non-squashing boxes problem (version 1).at n=29A089054
- Smallest prime(k) such that prime(k)-prime(k-n) is equal to prime(k+1)-prime(k).at n=3A089344