9225
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
- 18
- Divisor Sum
- 16926
- Proper Divisor Sum (Aliquot Sum)
- 7701
- 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
- 4800
- Möbius Function
- 0
- Radical
- 615
- Omega Function (Ω)
- 5
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 228
- 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
- Discriminants of totally real quartic fields (see comments).at n=34A002769
- E.g.f. 1 + x*exp(x) + x^2*exp(2*x).at n=9A003013
- a(n) = n*(11*n - 1)/2.at n=41A022268
- Number of binary Lyndon words containing n letters of each type; periodic binary sequences of period 2n with n zeros and n ones in each period.at n=10A022553
- Number of aperiodic necklaces of n beads of 2 colors, 10 of them black.at n=9A032168
- Number of partitions satisfying cn(1,5) + cn(4,5) <= cn(0,5).at n=44A039860
- Number of ordered factorizations with 3 levels of parentheses indexed by prime signatures: A050358(A025487(n)).at n=16A050359
- Numbers n such that n | 12^n + 11^n + 10^n + 9^n + 8^n + 7^n + 6^n + 5^n + 4^n + 3^n.at n=38A057289
- n is odd and sum of digits of n equals the numbers of divisors of n.at n=39A057532
- Positive numbers whose product of digits is 10 times their sum.at n=39A062043
- Write 0, 1, 2, 3, 4, ... in a triangular spiral, then a(n) is the sequence found by reading the terms along the line from 0 in the direction 0, 7, ...at n=45A062725
- Pair the odd numbers such that the k-th pair is (r, r+2k) where r is the smallest odd number not included earlier: (1, 3), (5, 9), (7, 13), (11, 19), (15, 25), (17, 29), (21, 35), (23, 39), (27, 45), ... This is the sequence of the product of the members of pairs.at n=23A075320
- a(1) = 1, a(2) = 2, next terms up to a(2n-1) are obtained by multiplying previous terms a(n-1) by n+1, a(n-2) by n+2 etc. a(2) by (2n-2) and a(1) by 2n-1. On similar lines a(2n) = 2n*a(2n-2), a(2n+1) = (2n+1)*a(2n-1) and so on.at n=40A109844
- a(1) = 1, a(2) = 2; a(n) = lcm(n, a(n-2)), a(n+1) = lcm((n+1), a(n-3)) and so on until a(2n-1) = lcm(2n-1, a(1)). Then a(2n) = lcm(2n, a(2n-2)) and so on.at n=40A109849
- Upper half of Hankel determinant number wall for A004148.at n=68A123634
- Numbers which converge to 2592 under repeated application of the powertrain map of A133500.at n=6A135384
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, -1), (-1, -1, 0), (-1, 1, -1), (1, -1, 0), (1, 0, 1)}.at n=10A148217
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (0, 0, 1), (0, 1, -1), (1, 0, 1), (1, 1, -1)}.at n=7A150710
- Partial sums of A151782.at n=25A151793
- 3 times 9-gonal (or nonagonal) numbers: a(n) = 3*n*(7*n-5)/2.at n=30A152759