5218
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
- 7830
- Proper Divisor Sum (Aliquot Sum)
- 2612
- 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
- 2608
- Möbius Function
- 1
- Radical
- 5218
- 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
- 54
- 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
- yes
- Odd
- no
Appears in sequences
- 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 72.at n=2A031570
- Numbers having four 3's in base 5.at n=24A043364
- Positive numbers whose product of digits is 5 times their sum.at n=35A062382
- Numbers k such that k divides the sum of digits of 8^k.at n=13A062933
- Interprimes (A024675) which are of the form s*prime, s=2.at n=38A075277
- Number of connected 3-colorable (i.e., chromatic number <= 3) simple graphs on n nodes.at n=7A076322
- Number of subsets S of {1,2,...,n} which contain a number that is greater than the sum of the other numbers in S.at n=25A095944
- Number of compositions of n with first part 3 and no equal adjacent parts; this is column 3 of the array in A096568.at n=19A096571
- Number of partitions of n into deficient numbers.at n=31A097797
- Number of partitions of the n-th deficient number into deficient numbers.at n=24A097799
- Diagonal sums of number triangle A122919.at n=8A122920
- Numbers n whose reverse binary representation has the following property: let a 0 mean "halving" and a 1 mean "k -> 3k+1". The number describes an operation k -> f_n(k). If the equation f_n(k) = k has an integer solution, n is a term in the sequence.at n=40A125754
- Numbers n whose reverse binary representation has the following property: let a 0 mean "halving" and a 1 mean "k -> 3k+1". The number describes an operation k -> f_n(k). If the equation f_n(k) = k has a positive integer solution, n is a term in the sequence.at n=26A125756
- a(n) = C(2,n) DELTA C(0,n).at n=40A147721
- Number of 0..2 integer arrays v[1..n] of length n with all autocorrelation values sum(i){v[i]*v[i-k]} distinct for k in 0..n-1.at n=10A171308
- Number of 0..n-1 integer arrays v[1..11] of length 11 with all autocorrelation values sum(i){v[i]*v[i-k]} distinct for k in 0..10.at n=2A171362
- Parameters n for which the Tate-Shafarevich group Ш of the elliptic curve y^2=x^3-n has order 16.at n=18A179140
- Coefficient of x in the reduction of the n-th Fibonacci polynomial by x^3->x^2+2.at n=14A192799
- Least k such that k*30^n-1 , k*30^n+1, and 2*k*30^n-1 are prime; that is, twin primes and a Sophie Germain prime.at n=14A212956
- a(n) is conjectured to be the largest power k for which k divides the sum of digits of n^k.at n=7A220365