5131
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 10
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 5872
- Proper Divisor Sum (Aliquot Sum)
- 741
- 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
- 4392
- Möbius Function
- 1
- Radical
- 5131
- 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
- no
- 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
- no
- Odd
- yes
Appears in sequences
- "Half-Catalan numbers": a(n) = Sum_{k=1..floor(n/2)} a(k)*a(n-k) with a(1) = 1.at n=14A000992
- Coordination sequence T4 for Zeolite Code MEL.at n=46A008153
- a(n) = floor( n*(n-1)*(n-2)/29 ).at n=54A011911
- Integers that are squarefree and also the sum of first k squarefrees for some k.at n=47A013932
- Expansion of 1/(1-x^4-x^5-x^6-x^7-x^8-x^9-x^10).at n=34A017832
- Numbers that are the sum of 4 distinct positive cubes in exactly 3 ways.at n=22A025410
- Numbers that are the sum of 4 distinct positive cubes in 3 or more ways.at n=23A025413
- Numbers k such that k-th and (k+1)-st term of A038593 differ by 5.at n=6A038636
- Numbers ending with '1' that are the difference of two positive cubes.at n=24A038856
- a(n)=(s(n)+2)/9, where s(n)=n-th base 9 palindrome that starts with 7.at n=23A043078
- a(n)=T(2n-1,n), array T given by A048212.at n=37A048221
- Expansion of ( 1-x-x^2 ) / ( 1-2*x-2*x^2+x^3+x^4 ).at n=10A052960
- a(1) = 7; a(n) is smallest number > a(n-1) such that the juxtaposition a(1)a(2)...a(n) is a prime.at n=35A074343
- Number of n-digit base-5 deletable primes.at n=9A096238
- a(n) is the number of positive integers <= 10^n that are divisible by no prime exceeding 3.at n=38A100752
- Indices of primes in sequence defined by A(0) = 63, A(n) = 10*A(n-1) + 53 for n > 0.at n=12A101538
- a(1) = 1; for n > 1, a(n) is the least k > a(n-1) such that a(n) + a(n-1) is square and a(n) - a(n-1) is prime.at n=17A108972
- Semiprimes for which both the sum and the product of the digits is also a semiprime.at n=26A118690
- a(n) = a(n-2) + a(n-4) + a(n-5) + a(n-7) + a(n-8) + a(n-10) for n >= 10, with a(0) = ... = a(9) = 1.at n=29A122762
- Where records occur in A082467.at n=26A129302