16020
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 9
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 36
- Divisor Sum
- 49140
- Proper Divisor Sum (Aliquot Sum)
- 33120
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4224
- Möbius Function
- 0
- Radical
- 2670
- Omega Function (Ω)
- 6
- 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
- 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
- Square array T(k,n) by antidiagonals, where T(k,n) is number of ways of placing n identifiable nonnegative intervals with a total of exactly k starting and/or finishing points.at n=59A059515
- Split positive integers into extending even groups and sum: 1+2, 3+4+5+6, 7+8+9+10+11+12, 13+14+15+16+17+18+19+20, ...at n=20A061317
- Number of unlabeled, connected graphs on n vertices which have no induced subgraph isomorphic to a P5 and are chordal and prime.at n=10A079569
- Least common multiple of prime(n+1)-1 and prime(n)-1.at n=40A083554
- a(n) = lcm(p-1, p+1) where p is the n-th prime.at n=40A084921
- Number of points of self-intersection of the path of a billiard ball traveling at a 45-degree angle on a prime(n) X prime(n+1) billiard table. Also equal to 1/2 the number of the lattice points lying within a prime(n) X prime(n+1) rectangle.at n=40A099407
- Numbers k such that 3*10^k + 8*R_k - 7 is a prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=18A102978
- Binomial transform of A100060.at n=15A106399
- Negative numbers written in a bits-of-Pi/primorial base system.at n=33A109839
- a(1)=1, a(n) = first index i (> a(n-1)), where A112046(i) gets a value distinct from any values A112046(1)..A112046(a(n-1)).at n=40A112051
- On the standard 33-hole cross-shaped peg solitaire board, the number of distinct board positions after n jumps that can still be reduced to one peg at the center (starting with the center vacant).at n=9A112738
- On the standard 33-hole cross-shaped peg solitaire board, the number of distinct board positions after n jumps that can still be reduced to one peg at the center (starting with the center vacant).at n=22A112738
- Triangle of numbers obtained from the partition array A134274.at n=23A134275
- 12 times pentagonal numbers: a(n) = 6*n*(3*n-1).at n=30A153792
- a(n) = 1458*n - 18.at n=10A157508
- a(n) = 1000*n + 20.at n=15A157510
- Number of (1,0)-steps at level 0 in all weighted lattice paths in L_n.at n=11A182895
- Molecular topological indices of the sun graphs.at n=14A192845
- a(n) = (prime(n)^2 - 1)/2 for n >= 2.at n=39A216244
- Expansion of x^2*(1+x^2) / ( (x^2-x+1)*(-x^2-x+1)*(1+x+x^2) ).at n=23A227047