7867
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 28
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 7868
- 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
- 7866
- Möbius Function
- -1
- Radical
- 7867
- 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
- 52
- 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
- 993
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Numbers k such that the continued fraction for sqrt(k) has period 86.at n=19A020425
- a(n) = least m such that if r and s in {1/1, 1/3, 1/5, ..., 1/(2n-1)} satisfy r < s, then r < k/m < (k+4)/m < s for some integer k.at n=29A024847
- Primes that are palindromic in base 9.at n=19A029977
- 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 87.at n=27A031585
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 42 ones.at n=35A031810
- Base-9 palindromes that start with 1.at n=36A043028
- Numbers having four 1's in base 9.at n=24A043460
- Numbers whose base-4 representation contains exactly three 2's and three 3's.at n=31A045151
- Discriminants of imaginary quadratic fields with class number 11 (negated).at n=29A046008
- Primes whose sum of digits is the perfect number 28.at n=15A048517
- Primes p from A031924 such that A052180(primepi(p)) = 17.at n=9A052234
- Primes p with property that p concatenated with its emirp p' (prime reversal) forms a palindromic prime of the form 'primemirp' (rightmost digit of p and leftmost digit of p' are blended together - p and p' palindromic allowed).at n=40A054217
- Prime number spiral (clockwise, Northeast spoke).at n=16A054553
- Second term of strong prime 5-tuples: p(m)-p(m-1) > p(m+1)-p(m) > p(m+2)-p(m+1) > p(m+3)-p(m+2).at n=21A054809
- Primes starting and ending with 7.at n=30A062334
- Primes p such that sum of even digits of p equals sum of odd digits of p.at n=36A076167
- a(n) = prime(n*(n+1)/2+3).at n=44A078724
- Initial term in sequence of four consecutive primes separated by 3 consecutive differences each <=6 (i.e., when d=2,4 or 6) and forming d-pattern=[6, 4,2]; short d-string notation of pattern = [642].at n=17A078855
- Primes p such that the differences between the 5 consecutive primes starting with p are (6,4,2,4).at n=7A078961
- Numbers k such that k, sigma(k) and phi(k) have the same decimal digits (ignoring multiplicity).at n=5A082059