4981
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 22
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 5292
- Proper Divisor Sum (Aliquot Sum)
- 311
- 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
- 4672
- Möbius Function
- 1
- Radical
- 4981
- 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
- 90
- Smith Number
- yes
- 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
- Leading term of Stirling's approximation to n!, sqrt(2*Pi)*n^(n+(1/2))/e^n, rounded up.at n=7A005395
- Coordination sequence T3 for Zeolite Code MTW.at n=46A008198
- Numbers whose base-4 representation contains exactly four 1's and two 3's.at n=23A045131
- Let S(t) = 1 + s_1*t + s_2*t^2 + ... satisfy S' = -S/(2 + S); sequence gives numerators of s_n.at n=12A058955
- a(n) is the concatenation of n, (n-1)^2, (n-2)^3, (n-3)^4, ..., 2^(n-1) and 1.at n=3A068705
- a(n) = number of m such that A080737(m) <= 2n.at n=32A080740
- a(1) = 1 and then least squarefree number such that every partial concatenation of 2 or more terms is a prime.at n=39A086475
- Numbers n such that n*359# +-1 are twin primes, where 359# = 72nd primorial (A002110(72)).at n=5A087907
- Expansion of -x*(-1-x+x^2) / ( 1-2*x-3*x^2+x^3 ).at n=8A095125
- Reversible Smith numbers, i.e., Smith numbers whose reversal is also a Smith number.at n=37A104171
- Logarithmic derivative of A112936 such that a(n)=(1/3)*A112936(n+1) for n>0, where A112936 equals the INVERT transform (with offset) of triple factorials A008544.at n=4A112937
- Number of ordered triples (i,j,k) in range [0..n] satisfying i == j mod 2 and j == k mod 3.at n=30A115520
- Khinchin primes: values of n such that the concatenation of the first n decimal digits of Khinchin's constant is prime.at n=4A118327
- The (1,1)-entry in the matrix M^n, where M is the 7 X 7 Cartan matrix [2,-1,0,0,0,0,0; -1,2,-1,0,0,0,0; 0,-1,2,-1,0,0,-1; 0,0,-1,2,-1,0,0; 0,0,0,-1,2,-1,0; 0,0,0,0,-1,2,0; 0,0,-1,0,0,0,2].at n=8A125501
- Sequence generated from the E6 Cartan matrix.at n=8A126567
- Top-left "head" entry of the n-th power of the E8 Cartan matrix.at n=8A126569
- Integers of the form (x^3)/6 + (x^2)/2 + x + 1.at n=10A127876
- Positions of highly powerful numbers in the EKG sequence.at n=16A141422
- a(n) = n*(n^2+4).at n=17A155965
- a(n) is the n-th J_8-prime (Josephus_8 prime).at n=8A163788