4087
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 4216
- Proper Divisor Sum (Aliquot Sum)
- 129
- 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
- 3960
- Möbius Function
- 1
- Radical
- 4087
- 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
- 157
- 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
- a(n) = floor(1000*log_2(n)).at n=16A004265
- a(n) = round(1000*log_2(n)).at n=16A004266
- Products of 2 successive primes.at n=17A006094
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly nine 1's.at n=9A020445
- Numbers k such that Fib(k) == 13 (mod k).at n=25A023178
- Coordination sequence T3 for Zeolite Code ITE.at n=44A027371
- "DFJ" (bracelet, size, labeled) transform of 1,3,5,7...at n=7A032212
- "EFJ" (unordered, size, labeled) transform of 1,3,5,7,...at n=7A032300
- Squares of primes or products of pairs of consecutive primes.at n=35A033476
- a(1) = 1; a(n) is smallest number >= a(n-1) such that the juxtaposition a(1)a(2)...a(n) is a prime.at n=37A033680
- Sums of 11 distinct powers of 2.at n=8A038462
- a(n) is the smallest composite number c such that A002110(n) + c is prime.at n=16A038771
- Numbers having three 7's in base 8.at n=20A043451
- Numbers whose base-5 representation contains exactly two 1's and three 2's.at n=22A045228
- Discriminants of real quadratic fields with class number 2 and related continued fraction period length of 16.at n=39A051981
- a(1)=2, a(n+1) is the smallest integer > a(n) such that the smallest prime factor of a(n+1) is the largest prime factor of a(n).at n=36A057602
- Composite numbers not divisible by 5 which in base 5 contain their largest proper factor as a substring.at n=0A063889
- Semiprimes p1*p2 such that p2 mod p1 = 6, with p2 > p1.at n=41A064904
- Numbers that in base 2 need twelve 'Reverse and Add' steps to reach a palindrome.at n=27A066133
- Numbers k such that k and 3^k end with the same two digits.at n=40A067749