13720
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 32
- Divisor Sum
- 36000
- Proper Divisor Sum (Aliquot Sum)
- 22280
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4704
- Möbius Function
- 0
- Radical
- 70
- Omega Function (Ω)
- 7
- Little Omega Function (ω)
- 3
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
- 32
- 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
- Degrees of irreducible representations of Held group He.at n=25A003912
- Triangle of coefficients in expansion of (2 + 7*x)^n.at n=18A013623
- Number of partitions of n into parts not of the form 11k, 11k+2 or 11k-2. Also number of partitions with 1 part of size 1 and differences between parts at distance 4 are greater than 1.at n=44A035945
- Triangle whose (i,j)-th entry is binomial(i,j)*7^(i-j)*2^j.at n=17A038268
- Triangle whose (i,j)-th entry is binomial(i,j)*7^(i-j)*10^j.at n=11A038276
- Triangle whose (i,j)-th entry is binomial(i,j)*10^(i-j)*7^j.at n=13A038309
- Theta series of E_8 lattice with respect to midpoint of edge.at n=9A045819
- Numbers k such that sigma(k) - usigma(k) is a square and sets a new record for such squares.at n=22A063840
- Numbers k such that the number of steps to reach 1 in '3x+1' problem equals tau(k), the number of divisors of k.at n=20A070980
- Nonsquares with A072594(n) = 0.at n=27A072596
- Numbers k such that sopfr(k)=tau(k).at n=28A078511
- a(n) = n*(2*n^2 -3*n +7)/6 = C(n, 1) + C(n, 2) + 2*C(n, 3).at n=34A081489
- Numbers with at least two 3s in their prime signature.at n=34A109399
- a(n) = n*(n+13)*(n+14)/6.at n=35A111144
- Triangle, read by rows, where T(n,k) = A049020([n/2],k)*A049020([(n+1)/2],k).at n=70A124526
- If (a_n) is a sequence then let L(a_n)=(b_n) where b_n = a_n^2 - a_{n-1} a_{n+1}. The given sequence is the rows of the triangle obtained by computing L^2(binomial(n,k)).at n=25A140982
- Lower triangular array called S2hat(-4) related to partition number array A144284.at n=31A144285
- Lower triangular array called S2hat(-4) related to partition number array A144284.at n=40A144285
- Numbers of the form p^3*q^3*r where p, q, and r are prime.at n=22A179688
- Number of nX3 binary arrays with each sum of a(1..i,1..j) no greater than i*j/2 and rows and columns in nondecreasing order.at n=11A183410