5821
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 5822
- 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
- 5820
- Möbius Function
- -1
- Radical
- 5821
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 142
- 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
- 764
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- From a Goldbach conjecture: records in A185091.at n=35A002092
- a(0) = 1, a(n) = 11*n^2 + 2 for n>0.at n=23A010003
- Numbers k such that the continued fraction for sqrt(k) has period 43.at n=13A020382
- n! has a palindromic prime number of digits.at n=19A035067
- Numbers having three 7's in base 9.at n=30A043483
- Numbers which, when expressed as a sum of distinct primes with maximum product, use a non-maximal number of primes.at n=24A053020
- Primes p such that x^5 == 2 (mod p) has five solutions.at n=39A059858
- Positive numbers whose product of digits is 5 times their sum.at n=41A062382
- Leading diagonal of triangle in A072467.at n=14A072468
- First column of array in A081998.at n=43A082000
- Numbers k such that (k! - 2)/2 is a prime.at n=17A082671
- Numbers n such that when the digits of Fibonacci(n) are sorted into decreasing order and zeros are dropped it is a prime.at n=41A082922
- Numbers containing no zero digits in bases 3 to 10.at n=18A085509
- Lesser number n of a pair such that neither n nor n+1 contain the digit zero in bases 3 to 10.at n=5A085828
- Primes which when concatenated with their reverse and incremented by 2 yield a new prime.at n=35A088883
- Primes of the form 60*n + 1.at n=41A088955
- Primes which when multiplied by their largest digit and 1 is subtracted form another prime.at n=38A090195
- Primes whose base-17 expansion is a (valid) decimal expansion of a prime.at n=36A090713
- Primes of the form x^2+xy+24y^2, with x and y nonnegative.at n=40A107001
- Primes of the form x^2 + 84y^2.at n=39A107198