4020
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 6
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 24
- Divisor Sum
- 11424
- Proper Divisor Sum (Aliquot Sum)
- 7404
- 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
- 1056
- Möbius Function
- 0
- Radical
- 2010
- Omega Function (Ω)
- 5
- 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
- 69
- 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
- Some permutation of digits is a factorial number.at n=39A007926
- Some nontrivial permutation of digits is a factorial number.at n=33A007927
- Coordination sequence T2 for Zeolite Code AHT.at n=43A009867
- Coordination sequence T4 for Zeolite Code iRON.at n=45A009884
- Coordination sequence T3 for Zeolite Code VNI.at n=39A009909
- Coordination sequence T2 for Zeolite Code WEI.at n=44A009918
- Continued fraction for log(15/2).at n=64A016535
- Number of 3's in n-th term of A007651.at n=35A022468
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = (composite numbers), t = (odd natural numbers).at n=21A024590
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (composite numbers), t = (odd natural numbers).at n=20A025104
- a(n) = Sum_{k=0..n} T(n,k), T given by A026758.at n=11A026765
- Number of aperiodic binary strings of length n; also number of binary sequences with primitive period n.at n=12A027375
- Number of n-vertex labeled graphs that are gracefully labeled trees.at n=8A033472
- Decimal part of cube root of n starts with 9: first term of runs.at n=14A034135
- Product of the lengths of the cycle types of the permutation created by duality and reversal on the partitions of n.at n=13A036046
- Number of partitions satisfying (cn(0,5) = 0 and cn(1,5) <= cn(2,5) and cn(1,5) <= cn(3,5) and cn(4,5) <= cn(2,5) and cn(4,5) <= cn(3,5)).at n=43A036812
- a(n) = prime(n)*prime(n+1) - prime(n+1).at n=17A037167
- Row sums of triangle T(m,n) = number of solutions to 1 <= a(1) < a(2) < ... < a(m) <= n, where gcd(a(1), a(2), ..., a(m), n) = 1, in A020921.at n=11A038199
- Coordination sequence T4 for Zeolite Code AFN.at n=45A038404
- Denominators of continued fraction convergents to sqrt(404).at n=3A041767