7245
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 24
- Divisor Sum
- 14976
- Proper Divisor Sum (Aliquot Sum)
- 7731
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- yes
Derived Values
- Euler's Totient
- 3168
- Möbius Function
- 0
- Radical
- 2415
- Omega Function (Ω)
- 5
- Little Omega Function (ω)
- 4
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
- 70
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- 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
- Number of partitions of n that do not contain 1 as a part.at n=41A002865
- Odd abundant numbers (odd numbers m whose sum of divisors exceeds 2m).at n=13A005231
- Odd primitive abundant numbers.at n=10A006038
- cosh(log(x+1)-arcsinh(x))=1+3/4!*x^4-30/5!*x^5+180/6!*x^6-945/7!*x^7...at n=8A013279
- Euler transform of Thue-Morse sequence A001285.at n=21A029877
- a(n+1) = Sum_{k=0..floor(n/tau)} a(k) * a(n-k), where tau = (1+sqrt(5))/2.at n=14A030040
- Number of chiral n-ominoes in n-1 space.at n=17A045649
- Integer part of log(n^n)^(1 + log(1 + log(1 + n))).at n=16A062451
- Number of compositions (ordered partitions) of n that are concave-down sequences.at n=48A070211
- Odd primitive numbers such that n! divided by product of factorials of all proper divisors of n is not an integer.at n=10A075460
- Numbers k such that k^4 has k as a substring of its decimal expansion.at n=41A075904
- Sum of numbers that can be written as t*n + u*(n+1) for nonnegative integers t,u in exactly one way.at n=8A076454
- 2-apexes of omega: numbers k such that omega(k-2) < omega(k-1) < omega(k) > omega(k+1) > omega(k+2), where omega(m) = the number of distinct prime factors of m.at n=40A076762
- 2-nadirs of phi: numbers k such that phi(k-2) > phi(k-1) > phi(k) < phi(k+1) < phi(k+2).at n=36A076773
- Lexicographically earliest increasing sequence of relatively prime numbers with nondecreasing number of divisors. a(0) = 1, tau(a(n+1)) >= tau(a(n)) and GCD(a(n),a(n+1)) = 1.at n=40A076963
- Starting positions of strings of three 5's in the decimal expansion of Pi.at n=5A083620
- Number of partitions of n including 3, but not 1.at n=43A085811
- 3 times hexagonal numbers: a(n) = 3*n*(2*n-1).at n=35A094159
- Triangle read by rows giving the coefficients of formulas generating each variety of S1(n,k) (unsigned Stirling numbers of first kind). The p-th row (p>=1) contains T(i,p) for i=1 to 2*p, where T(i,p) satisfies Sum_{i=1..2*p} T(i,p) * C(n,i).at n=28A094216
- Combinatorial triangle !n. This table read by rows gives the coefficients of general sum formulas of n-th left factorials (A003422). The k-th row (k>=1) contains T(i,k) for i=1 to 2*k and k=1 to n-2, where T(i,k) satisfies !n = n + Sum_{k=1..n-2} Sum_{i=1..2*k} T(i,k) * C(n-k-1,i).at n=28A102639