2620
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
- 1
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 5544
- Proper Divisor Sum (Aliquot Sum)
- 2924
- 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
- 1040
- Möbius Function
- 0
- Radical
- 1310
- Omega Function (Ω)
- 4
- 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
- yes
- Harshad Number
- yes
- Narcissistic Number
- no
- Collatz Steps
- 146
- 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
- Number of self-inverse permutations on n letters, also known as involutions; number of standard Young tableaux with n cells.at n=9A000085
- Smaller of an amicable pair: (a,b) such that sigma(a) = sigma(b) = a+b, a < b.at n=2A002025
- Coordination sequence T3 for Zeolite Code DDR.at n=32A008073
- Coordination sequence T6 for Zeolite Code MFS.at n=32A008178
- Table T(n,k) giving number of permutations of [1..n] with order dividing k, read by antidiagonals.at n=46A008307
- Coordination sequence T1 for Zeolite Code -CLO.at n=45A009850
- Number of 5-ary search trees on n keys.at n=12A019499
- Coordination sequence T2 for Zeolite Code SAO.at n=40A019572
- Coordination sequence T3 for Zeolite Code SAO.at n=40A019573
- a(n) = 1*t(n) + 2*t(n-1) + ...+ k*t(n+1-k), where k=floor((n+1)/2) and t is A001950 (upper Wythoff sequence).at n=21A023867
- s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = (odd natural numbers), t = A001950 (upper Wythoff sequence).at n=17A024600
- a(n) = s(1)s(n) + s(2)s(n-1) + ... + s(k)s(n+1-k), where k = [ (n+1)/2 ], s = A001950 (upper Wythoff sequence).at n=15A024689
- s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (natural numbers), t = A001950 (upper Wythoff sequence).at n=20A024864
- s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (odd natural numbers), t = A001950 (upper Wythoff sequence).at n=16A025114
- s(1)s(n) + s(2)s(n-1) + ... + s(k)s(n-k+1), where k = [ n/2 ], s = A001950 (upper Wythoff sequence).at n=14A025122
- a(n) = a(1)*a(n-1) + a(2)*a(n-2) + ... + a(n-3)*a(3) for n >= 4, with initial terms 0, 2, 1, 0.at n=16A025253
- a(n) = A027011(2n+1, n+4).at n=3A027019
- Coordination sequence T1 for Zeolite Code ITE.at n=35A027369
- T(n, 2*n-5), T given by A027960.at n=10A027967
- Numbers k such that k^2 has only even digits.at n=43A030097