7445
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 8940
- Proper Divisor Sum (Aliquot Sum)
- 1495
- 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
- 5952
- Möbius Function
- 1
- Radical
- 7445
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 39
- 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(n*(n - 1)*(n - 2)/32).at n=63A011914
- The sequence m(n) in A022905.at n=42A022907
- Number of partitions in parts not of the form 11k, 11k+3 or 11k-3. Also number of partitions with at most 2 parts of size 1 and differences between parts at distance 4 are greater than 1.at n=38A035946
- Number of primes between n*100000 and (n+1)*100000.at n=6A038825
- Numerators of continued fraction convergents to sqrt(76).at n=7A041134
- Numerators of continued fraction convergents to sqrt(304).at n=9A041572
- Numerators of continued fraction convergents to sqrt(931).at n=5A042800
- G.f.: ( 1 + x + x^2 - x^3 - x^4 - sqrt( 1 - 2 x - 5 x^2 - 4 x^3 - 3 x^4 - 4 x^5 - x^6 + 2 x^7 + x^8 ) ) / ( 2 x (1 + x) ).at n=10A050262
- E.g.f. A(x) is inverse to F(x) = x*exp(-x)/(1+x).at n=5A052885
- Number of n-digit primes beginning with n.at n=5A088755
- Triangle of 3rd central factorial numbers T(n,k).at n=18A098436
- Start to read the sequence digit by digit and erase the first "1" you encounter, then the first "2", the first "3", etc., until the first "0"; go on from there and erase again the first "1", the first "2", etc., until "0" -- and so on, cyclically until the end of the (infinite) sequence. Concatenate what is left. The result is the concatenation of all integers of the sequence.at n=9A108710
- Apply partial sum operator 5 times to partition numbers.at n=10A120477
- a(n) = number of distinct prime divisors (taken together) of numbers of the form 2x^2+1 for x<=10^n.at n=3A144851
- Similar to A072921 but starting with 2.at n=36A152231
- Number of different hook length multisets of partitions of n.at n=35A180652
- Expansion of 1/(1 - x - x^2 + x^5 - x^7).at n=21A204631
- Number of n X n 0..3 arrays with no occurrence of three equal elements in a row horizontally or vertically, and new values 0..3 introduced in row major order.at n=2A205304
- Number of nX3 0..3 arrays with no occurrence of three equal elements in a row horizontally or vertically, and new values 0..3 introduced in row major order.at n=2A205305
- T(n,k)=Number of nXk 0..3 arrays with no occurrence of three equal elements in a row horizontally or vertically, and new values 0..3 introduced in row major order.at n=12A205310