4545
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
- 12
- Divisor Sum
- 7956
- Proper Divisor Sum (Aliquot Sum)
- 3411
- 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
- 2400
- Möbius Function
- 0
- Radical
- 1515
- Omega Function (Ω)
- 4
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 139
- 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
- Coordination sequence T3 for Zeolite Code FER.at n=41A008108
- Coordination sequence T1 for Zeolite Code HEU.at n=44A008116
- Coordination sequence T6 for Zeolite Code NES.at n=43A008210
- arcsin(sec(x)*arcsin(x))=x+5/3!*x^3+93/5!*x^5+4545/7!*x^7+443065/9!*x^9...at n=3A012784
- Numbers k such that k | 14^k + 1.at n=46A015965
- Pseudoprimes to base 91.at n=38A020219
- Doublets: base-10 representation is the juxtaposition of two identical strings.at n=44A020338
- a(n) = position of 3*n^2 in sequence A025051 (numbers of form j*k + k*i + i*j, without repetitions, where 1 <= i <= j <= k).at n=38A025056
- a(n) = floor(10^5/n).at n=21A033427
- Number of partitions of n into parts not of form 4k+2, 24k, 24k+3 or 24k-3. Also number of partitions in which no odd part is repeated, with 1 part of size less than or equal to 2 and where differences between parts at distance 5 are greater than 1 when the smallest part is odd and greater than 2 when the smallest part is even.at n=46A036030
- Number of partitions satisfying 0 < cn(0,5) + cn(1,5) + cn(2,5) + cn(3,5) and 0 < cn(0,5) + cn(4,5) + cn(2,5) + cn(3,5).at n=29A039903
- Numerators of continued fraction convergents to sqrt(57).at n=8A041098
- Numerators of continued fraction convergents to sqrt(228).at n=2A041424
- Base-8 palindromes that start with 1.at n=25A043021
- Odd numbers with exactly 4 palindromic prime factors (counted with multiplicity).at n=34A046374
- a(n+1) = a(n) + n (if n is even), a(n+1) = a(n) * n (if n is odd).at n=9A047905
- a(n)=T(n,2), array T as in A049735.at n=38A049745
- a(n) = A050314(2n+1,1): column 1 of triangle.at n=20A050316
- a(0) = 0; a(n) = a(n-1) - n^2 if positive and new, otherwise a(n) = a(n-1) + n^2.at n=49A053461
- Numbers k such that (k + R(k)) / (k - R(k)) = +-11 where R(k) is the digit reversal of k (A004086).at n=4A062390