1901
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
- 2
- Divisor Sum
- 1902
- 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
- 1900
- Möbius Function
- -1
- Radical
- 1901
- 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
- 29
- 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
- yes
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 291
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Number of symmetrical planar partitions of n (planar partitions (A000219) that when regarded as 3-D objects have just one symmetry plane).at n=26A000784
- Number of free planar polyenoids with n nodes and symmetry point group C_{2v}.at n=18A000936
- a(n) = ceiling(n*phi^9), where phi is the golden ratio, A001622.at n=25A004964
- Primes p such that the NSW number A002315((p-1)/2) is prime.at n=13A005850
- Numbers n such that n, 2n+1, and 4n+3 all prime.at n=18A007700
- Coordination sequence T2 for Zeolite Code LAU.at n=31A008125
- Coordination sequence T1 for Banalsite.at n=26A008249
- Coordination sequence T2 for Banalsite.at n=26A008250
- Coordination sequence for 5-dimensional lonsdaleite.at n=7A008525
- Coordination sequence T4 for Zeolite Code -PAR.at n=31A009858
- Numbers k such that the continued fraction for sqrt(k) has period 5.at n=41A010337
- Primes that remain prime through 2 iterations of function f(x) = x + 6.at n=48A023241
- Primes that remain prime through 2 iterations of function f(x) = 4x + 3.at n=26A023250
- Primes that remain prime through 2 iterations of function f(x) = 9x + 8.at n=27A023267
- Primes that remain prime through 3 iterations of function f(x) = 4x + 3.at n=9A023281
- Primes that remain prime through 3 iterations of function f(x) = 9x + 8.at n=8A023298
- Primes that remain prime through 4 iterations of the function f(x) = 9x + 8.at n=4A023326
- Greatest prime divisor of prime(n)*prime(n-1) - 1.at n=43A023517
- a(n) = least m such that if r and s in {1/1, 1/4, 1/7,..., 1/(3n-2)} satisfy r < s, then r < k/m < s for some integer k.at n=29A024822
- Least m such that if r and s in {1/1, 1/3, 1/6,..., 1/C(n+1,2)} satisfy r < s, then r < k/m < s for some integer k.at n=21A024826