4245
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 6816
- Proper Divisor Sum (Aliquot Sum)
- 2571
- 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
- 2256
- Möbius Function
- -1
- Radical
- 4245
- Omega Function (Ω)
- 3
- Little Omega Function (ω)
- 3
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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 126
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- 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
- Coordination sequence T2 for Zeolite Code MTW.at n=43A008197
- Triangle of coefficients from fractional iteration of e^x - 1.at n=13A008826
- Coordination sequence T3 for Zeolite Code RTH.at n=45A009895
- n written in fractional base 6/4.at n=29A024637
- a(n) = sum of the numbers between the two n's in A026358.at n=33A026361
- a(n) = Sum_{k=0..floor(n/2)} T(n-k,k), T given by A026725.at n=17A026735
- Concatenation of n and n + 3.at n=41A032608
- Numbers in which all pairs of consecutive base-6 digits differ by 2.at n=45A033084
- Convolution of natural numbers n >= 1 with Fibonacci numbers F(k), for k >= -5, with F(-n)=(-1)^(n+1)*F(n);.at n=20A037141
- Numbers whose base-4 representation contains exactly two 0's and four 1's.at n=16A045027
- Discriminants of real quadratic fields with class number 2 and related continued fraction period length of 2.at n=41A051967
- Discriminants of real quadratic fields of ERD-type with class groups of exponent 2 and discriminants of the form D = r^2*k^2+4k, k odd.at n=40A051992
- Sum of numbers in range 10*n to 10*n+9.at n=42A053743
- Euler transform applied twice to partition triangle A008284.at n=63A055885
- Number of chains of n-3 partitions in the reduced partition lattice on n elements.at n=3A059355
- Numbers k that divide A062273(k).at n=12A077579
- Matrix product of unsigned Stirling1-triangle |A008275(n,k)| and unsigned Lah-triangle |A008297(n,k)|.at n=17A079640
- Where records appear in A109890.at n=51A111243
- Positions of 13 after decimal point in decimal expansion of Pi.at n=43A134213
- Composites that are the sum of two, three, four and five consecutive composite numbers.at n=4A151745