12221
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 8
- Digital Root
- 8
- Palindromic Number
- yes
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 13566
- Proper Divisor Sum (Aliquot Sum)
- 1345
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 11000
- Möbius Function
- 0
- Radical
- 1111
- Omega Function (Ω)
- 3
- 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
- 94
- 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
- a(n) = (5*n^2 + 1)*n^2 / 6.at n=11A008354
- Numbers that are the sum of 3 positive cubes in exactly 3 ways.at n=3A025397
- Numbers that are the sum of 3 positive cubes in 3 or more ways.at n=3A025398
- Positive numbers for which the sum of digits equals the product of digits.at n=42A034710
- G.f.: A(x) = x*cycle_index(S5, B(x)-1), where B(x) is g.f. for A000598.at n=17A036670
- Composite numbers whose prime factors contain no digits other than 0 and 1.at n=4A036928
- k th digit of a(n) = number of different digits within 2 places of k (not including k).at n=11A039987
- k th digit of a(n) is the number of different digits within 3 of k (not including k).at n=11A039989
- Numbers that are palindromic, divisible by 11 and have an odd number of digits.at n=10A045571
- Palindromes with exactly 3 palindromic prime factors (counted with multiplicity).at n=17A046377
- Palindromes that are the sum of two shorter palindromes.at n=10A062696
- Numbers k such that sopf(k) = sopfr(k+1), where sopf(k) = A008472(k) and sopfr(k) = A001414(k).at n=21A064678
- Numbers k such that 10*k-1, 10*k-3, 10*k-7 and 10*k-9 are all prime.at n=41A064975
- Nonprimes whose sum of digits is equal to its product of digits.at n=34A066307
- n sets a new record for the number of integers k such that k is not of the form m + reverse(m) for any m and n occurs in the 'Reverse and Add' trajectory of k (cf. A067284).at n=18A067287
- Factorial expansion of A071156.at n=30A071158
- Numbers in base -3.at n=40A073785
- Palindromic odd numbers with exactly 3 prime factors (counted with multiplicity).at n=39A075814
- Palindromic numbers with prime middle digit.at n=48A076609
- All possible products in increasing order of two distinct members of the unary sequence 1, 11, 111, 1111, 11111, ...given by A000042.at n=5A077488