2391
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 3192
- Proper Divisor Sum (Aliquot Sum)
- 801
- 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
- 1592
- Möbius Function
- 1
- Radical
- 2391
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
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
- 120
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- Squarefree Number
- yes
- 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
- no
- Odd
- yes
Appears in sequences
- Coordination sequence T1 for Zeolite Code WEI.at n=35A009917
- Expansion of 1/(1 - x^2 - x^3 - x^4) = 1/((1 + x)*(1 - x - x^3)).at n=23A013979
- Convolution of primes with themselves.at n=12A014342
- Numbers k such that the continued fraction for sqrt(k) has period 38.at n=22A020377
- Numbers k such that Fibonacci(k) == -2 (mod k).at n=38A023163
- Dying rabbits: a(n) = a(n-1) + a(n-2) - a(n-5).at n=21A023435
- Number of distinct products i*j with 0 <= i, j <= n-th prime.at n=23A027419
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 15.at n=21A031513
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 20 ones.at n=35A031788
- Numbers k such that 221*2^k+1 is prime.at n=22A032487
- Multiplicity of highest weight (or singular) vectors associated with character chi_58 of Monster module.at n=33A034446
- a(n) = prime(n)*prime(n+1) - prime(n) - prime(n+1).at n=14A037165
- Number of partitions satisfying 0 < cn(0,5) + cn(1,5) + cn(4,5).at n=26A039900
- Denominators of continued fraction convergents to sqrt(103).at n=9A041185
- Denominators of continued fraction convergents to sqrt(338).at n=8A041639
- Numerators of continued fraction convergents to sqrt(647).at n=6A042242
- Numbers k such that string 2,7 occurs in the base 8 representation of k but not of k-1.at n=42A044210
- Numbers n such that string 4,6 occurs in the base 9 representation of n but not of n-1.at n=32A044293
- Numbers n such that string 9,1 occurs in the base 10 representation of n but not of n-1.at n=25A044423
- Numbers n such that string 4,6 occurs in the base 9 representation of n but not of n+1.at n=32A044674