7243
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
- 4
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 7244
- 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
- 7242
- Möbius Function
- -1
- Radical
- 7243
- 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
- 57
- 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
- 926
- 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 90.at n=11A020429
- T(2n+1,n+2), T given by A026758.at n=6A026877
- 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 85.at n=1A031583
- Number of partitions of n with equal nonzero number of parts congruent to each of 0, 1 and 4 (mod 5).at n=56A035584
- Primes with first digit 7.at n=43A045713
- Discriminants of imaginary quadratic fields with class number 13 (negated).at n=24A046010
- T(n,n+3), array T as in A047150.at n=7A047158
- Least prime in A023200 (lesser of 4-twins) such that the distance to the next 4-twin is 6*n.at n=38A052351
- Fourth term of strong prime quintets: p(m-2)-p(m-3) > p(m-1)-p(m-2) > p(m)-p(m-1) > p(m+1)-p(m).at n=18A054811
- a(n) is the smallest positive integer that cannot be obtained by using the number 2 at most n times and the operators +, -, *, /.at n=17A071997
- Expansion of 1/Sum_{k>=0} (-x)^Fibonacci(k).at n=15A080889
- Class 5+ primes (for definition see A005105).at n=34A081633
- Indices of primes which remain prime if any one digit is deleted (leading zeros allowed).at n=39A084375
- a(n) = 8*n^2 + 88*n + 43.at n=25A086760
- Primes whose reversal is a multiple of 23.at n=37A087767
- Beginning with 2, a(n+1) is the least prime == 1 (mod (Sum_{i=1..n} a(i))).at n=8A090474
- Primes whose base-17 expansion is a (valid) decimal expansion of a prime.at n=42A090713
- Primes p such that both prime(p) + prime(p+1) +/-1 are also primes.at n=36A093734
- Numerators of 1-2*HarmonicNumber(n)/(n+1).at n=11A093762
- Smallest prime P such that P# - Mersenne-prime(n) is prime.at n=21A098566