12345
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 19776
- Proper Divisor Sum (Aliquot Sum)
- 7431
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6576
- Möbius Function
- -1
- Radical
- 12345
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 50
- 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
- Concatenations of cyclic permutations of initial positive integers.at n=10A001292
- 11*n^2 + 11*n + 3.at n=33A006222
- Triangle of the gods: to get a(n), concatenate the decimal numbers 1,2,3,...,n.at n=4A007908
- a(0) = 0; for n>0, a(n) = 10*a(n-1) + n.at n=5A014824
- Positive numbers k such that k and 2*k are anagrams in base 6 (written in base 6).at n=4A023064
- Positive numbers k such that k and 3*k are anagrams in base 6 (written in base 6).at n=5A023065
- Positive numbers k such that k and 4*k are anagrams in base 6 (written in base 6).at n=3A023066
- Decimal representation of permutations of lengths 1, 2, 3, ... arranged lexicographically.at n=33A030299
- Smallest number that contains the numbers from 1 to n as substrings.at n=4A035239
- Subsets of natural numbers arranged in standard statistical (or Yates) order.at n=31A048794
- Append n to the previous term, reverse alternate terms.at n=4A053052
- Concatenate next digit at right hand end (where the next digit after 9 is again 0).at n=5A057137
- a(n) = floor(10^(n+1)/81).at n=5A057932
- Numbers in which each digit is the (immediate) successor of the previous one (if it exists) and 0 is considered the successor of 9.at n=37A059043
- String together the first n numbers in an order which minimizes the result.at n=4A060555
- Smallest number that begins with 1, has digits in order 123...901... and is divisible by n. If no such number exists then a(n) = 0.at n=14A061074
- Smallest number that begins with 1, has digits in order 123...901... and is divisible by n. If no such number exists then a(n) = 0.at n=4A061074
- Numbers n such that n divides the (left) concatenation of all numbers <= n written in base 22 (most significant digit on right).at n=10A061975
- a(n) is an n-digit number with digits in increasing order with 0 following 9 and this is maintained in the concatenation of any number of consecutive terms.at n=4A062273
- Terms of A007908 which are divisible by their index.at n=3A071269