2281
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 2282
- Proper Divisor Sum (Aliquot Sum)
- 1
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 2280
- Möbius Function
- -1
- Radical
- 2281
- Omega Function (Ω)
- 1
- Little Omega Function (ω)
- 1
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
- 151
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 339
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Mersenne exponents: primes p such that 2^p - 1 is prime. Then 2^p - 1 is called a Mersenne prime.at n=16A000043
- Number of ethylene derivatives with n carbon atoms.at n=10A000631
- Primes with 7 as smallest primitive root.at n=21A001126
- Degrees of primitive irreducible trinomials: n such that 2^n - 1 is a Mersenne prime and x^n + x^k + 1 is a primitive irreducible polynomial over GF(2) for some k with 0 < k < n.at n=11A001153
- Genus of modular group Gamma(n) = genus of modular curve Chi(n).at n=42A001767
- Centered 12-gonal numbers, or centered dodecagonal numbers: numbers of the form 6*k*(k-1) + 1.at n=19A003154
- a(n) = ceiling(n*phi^9), where phi is the golden ratio, A001622.at n=30A004964
- Class 4+ primes (for definition see A005105).at n=41A005108
- Primes p == 1 (mod 8), p = a^2 + 64*b^2 such that y^2 = x^3 + p*x has rank 2.at n=31A007766
- Coordination sequence T3 for Zeolite Code AET.at n=33A008009
- Coordination sequence T4 for Zeolite Code AET.at n=33A008010
- Coordination sequence T1 for Zeolite Code NAT.at n=32A008203
- Pisot sequence E(6,16), a(n) = floor( a(n-1)^2/a(n-2) + 1/2 ).at n=6A010915
- Primes p == 1 mod 8 such that 2 and -2 are both 4th powers (one implies other) mod p.at n=38A014754
- Numbers k such that the continued fraction for sqrt(k) has period 63.at n=2A020402
- Primes that remain prime through 2 iterations of function f(x) = 4x + 9.at n=41A023251
- Primes that remain prime through 2 iterations of function f(x) = 8x + 3.at n=27A023261
- Primes that remain prime through 3 iterations of function f(x) = 4x + 9.at n=9A023282
- Numbers whose least quadratic nonresidue (A020649) is 7.at n=34A025023
- Friedlander-Iwaniec primes: Primes of form a^2 + b^4.at n=45A028916