7220
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 11
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 18
- Divisor Sum
- 16002
- Proper Divisor Sum (Aliquot Sum)
- 8782
- 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
- 2736
- Möbius Function
- 0
- Radical
- 190
- Omega Function (Ω)
- 5
- 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
- 57
- 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
- Theta series of P_{10b} packing.at n=2A005954
- Partition function coefficients for square lattice spin 1 Ising model.at n=21A010107
- a(n) = n^2*(n+1).at n=19A011379
- a(n) = n^3 * Product_{p|n, p prime} (1 + 1/p).at n=18A033196
- a(n) = 5*n^2.at n=38A033429
- Numerators of continued fraction convergents to sqrt(218).at n=5A041406
- a(n) is smallest positive integer, distinct from any terms earlier in the sequence, such that (sum{k=1 to n}[a(k)]) divides (product{k=1 to n}[a(k)])*(sum{k=1 to n}[1/a(k)]).at n=15A058330
- Each c(i) is "multiply" (*) or "divide" (/). a(n) is number of choices for c(1), ..., c(n-1) so that 1 c(1) 2 c(2) 3,.., c(n-1) n is an integer.at n=19A058524
- Growth series for fundamental group of orientable closed surface of genus 5.at n=3A063815
- Numbers from A066112 that are neither square nor twice a square, i.e., are not in A028982 but are in A028983.at n=27A066134
- Numbers k such that phi(k) mod core(k) = 1 where core(k) is the squarefree part of k.at n=46A069946
- Sum of two powers of 19.at n=8A073214
- Numbers of the form Sum_{k=1..m} prime(r)^prime(k) for some values of m and r.at n=36A076794
- Orchard crossing number of complete bipartite graph K_{1,n}.at n=39A080838
- G.f. satisfies A^6 = BINOMIAL(A)^5 and also equals A090358^5.at n=4A090362
- Matrix logarithm of triangle A111536.at n=29A111541
- Column 1 of triangle A111541, which is the matrix logarithm of A111536.at n=6A111542
- This list of numbers a(i) has the property that every left-subset of length n > 0 of the numbers a(i) is divisible by i+n and are the largest such integers for every i.at n=17A113538
- Sum of the sizes of the Durfee squares of all partitions of n into odd parts.at n=44A116465
- a(n) = p^3 + p^2 where p = prime(n).at n=7A135178