11211
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 6
- Digital Root
- 6
- Palindromic Number
- yes
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 15504
- Proper Divisor Sum (Aliquot Sum)
- 4293
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7200
- Möbius Function
- -1
- Radical
- 11211
- Omega Function (Ω)
- 3
- 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
- 68
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- 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
- Numbers whose square is a palindrome.at n=25A002778
- Numbers that contain only 1's and 2's. Nonempty binary strings of length n in lexicographic order.at n=34A007931
- Triangle of Gaussian binomial coefficients [ n,k ] for q = 10.at n=12A022174
- a(1) = 3; a(n+1) = a(n)-th composite.at n=33A022451
- Numbers k such that k^2 is a palindrome with an odd number of digits.at n=24A028816
- Decimal expansion of a(n) is given by the first n terms of the periodic sequence with initial period 1,1,2.at n=4A037535
- Base 10 palindromes that start with 1.at n=34A043036
- Numbers whose base-7 representation contains exactly four 4's.at n=22A043412
- Numbers having four 1's in base 10.at n=21A043496
- Composite palindromes whose sum of prime factors is palindromic (counted with multiplicity).at n=18A046354
- Palindromes with exactly 3 distinct prime factors.at n=42A046393
- Product of the digits of n divides the sum of the digits of n.at n=46A055931
- Palindromes whose square is a palindrome; also palindromes whose sum of squares of digits is less than 10.at n=19A057135
- The zero-free, right-to-left factorial walk encoding for each rooted plane tree encoded by A014486. Sequence A071155 shown with factorial expansion (A007623).at n=28A071157
- Factorial expansion of A071156.at n=24A071158
- Integers whose decimal expansion start with 1, do not contain zeros and each successive digit to the right is at most one greater than the previous digit.at n=27A071159
- Leftmost 1 is converted to a 2, which then propagates one step at a time until it is rightmost; then it changes to a pair of 1's and the process repeats.at n=18A071762
- Variant of the factorial base representation of n.at n=35A072001
- Numbers n of the form k + reverse(k) for exactly two k.at n=25A072040
- Palindromic odd composite numbers that are the products of an odd number of distinct primes.at n=24A075808