5255
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 17
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 6312
- Proper Divisor Sum (Aliquot Sum)
- 1057
- 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
- 4200
- Möbius Function
- 1
- Radical
- 5255
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 85
- 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
- Smallest k such that the product of q/(q-1) over the primes from prime(n) to prime(n+k-1) is greater than 2.at n=47A001276
- Exactly 5 digits from {1,2,3,4,5,6,7,8,9} can precede a(n) to form a lucky number.at n=24A032701
- Smallest k>1 such that k(p-1)-1 is divisible by p^2, p=n-th prime.at n=20A039914
- Numerators of continued fraction convergents to sqrt(603).at n=5A042156
- Numbers having three 5's in base 10.at n=7A043511
- Numbers k>11 such that x^k + x^11 + x^10 + x^9 + x^8 + x^7 + x^6 + x^5 + x^4 + x^3 + x^2 + x + 1 is irreducible over GF(2).at n=33A057488
- Composite and every divisor (except 1) contains the digit 5.at n=39A062672
- Number of n-node connected graphs with one cycle, possibly of length 1 or 2.at n=10A068051
- Numbers using only the digits 2 and 5, that are both curved and straight.at n=25A072961
- Counts where both the odd composites (starting from 1) 1 mod 4 and 3 mod 4 are equal.at n=11A093182
- Numbers k such that (2^k-3)*2^k+1 is prime.at n=20A096149
- Lexicographically earliest sequence of increasing numbers whose digits satisfy the "Fractal Jump" rule using only the digits 2 and 5: keep the first digit "d" of the sequence, then jump over the next "d" digits and keep the digit "e" on which you have landed. Jump now over the next "e" digits and keep the digit "f" on which you have landed, etc. The succession "def..." of kept digits is the sequence itself.at n=13A105647
- Near-repdigit semiprimes with 5 as repeated digit.at n=17A105986
- n(k) is the minimum n that requires at least k to make 2*Prime[n]+Prime[n-k] a prime.at n=44A114237
- Numbers k such that k + prime(k) gives a triangular number.at n=27A115882
- Numbers k such that k concatenated with k-7 gives the product of two numbers which differ by 3.at n=1A116110
- Numbers k such that k concatenated with k-5 gives the product of two numbers which differ by 1.at n=2A116120
- p^2-p-1 that is not prime, where p is prime.at n=9A119609
- a(1) = a(2) = 1. a(n) = a(n-1) + (largest noncomposite {1 or prime} among the first n-2 terms of the sequence).at n=24A120761
- Table 1 on page 46 in the Witten reference.at n=18A122505