5520
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 12
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 40
- Divisor Sum
- 17856
- Proper Divisor Sum (Aliquot Sum)
- 12336
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 1408
- Möbius Function
- 0
- Radical
- 690
- Omega Function (Ω)
- 7
- Little Omega Function (ω)
- 4
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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 129
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- 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
- Denominator of B_{2n}/(-4n), where B_m are the Bernoulli numbers.at n=22A006863
- a(n) is least k such that k and 8k are anagrams in base n (written in base 10).at n=32A023100
- Numbers having period-4 6-digitized sequences.at n=29A031197
- Number of partitions of n into parts not of form 4k+2, 20k, 20k+7 or 20k-7. Also number of partitions in which no odd part is repeated, with at most 3 parts of size less than or equal to 2 and where differences between parts at distance 4 are greater than 1 when the smallest part is odd and greater than 2 when the smallest part is even.at n=44A036027
- Number of partitions of n into parts not of form 4k+2, 24k, 24k+11 or 24k-11. Also number of partitions in which no odd part is repeated, with at most 5 parts of size less than or equal to 2 and where differences between parts at distance 5 are greater than 1 when the smallest part is odd and greater than 2 when the smallest part is even.at n=42A036034
- A convolution triangle of numbers obtained from A034255.at n=11A048882
- Low-temperature susceptibility expansion for Kagome net (Potts model, q=3).at n=6A057399
- Least common multiple of all (k+1)'s, where the k's are the positive divisors of n.at n=44A057643
- Numbers k such that sigma(x) = k has exactly 7 solutions.at n=17A060663
- Numbers k such that k and its reversal are both multiples of 15.at n=41A062905
- Non-palindromic number and its reversal are both multiples of 15.at n=35A062914
- a(n) = binomial(2*n,n) mod ((n+1)*(n+2)*(n+3)).at n=21A065345
- Composite numbers k such that k - phi(k) divides sigma(k) - k.at n=9A068418
- Composite n such that n reduced mod(phi(n)) = sigma(n) reduced mod(n).at n=8A068495
- Numbers k such that k*tau(k)>4*prime(k).at n=38A068546
- Integer quotient defining A068418 is 3.at n=2A069737
- Least k such that k*n^n +/- 1 are twin primes.at n=42A076810
- Number of right triangles whose vertices are lattice points in {1,2,...,n} X {1,2,...,n}.at n=7A077435
- Numbers k such that d(phi(k)) = phi(d(k)), where d=A000005 and phi=A000010.at n=22A078148
- Largest number m such that a^n == 1 (mod m) whenever a is coprime to m.at n=43A079612