12312
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 9
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 40
- Divisor Sum
- 36300
- Proper Divisor Sum (Aliquot Sum)
- 23988
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 3888
- Möbius Function
- 0
- Radical
- 114
- Omega Function (Ω)
- 8
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 37
- 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
- yes
- Odd
- no
Appears in sequences
- Numbers k such that 2*3^k - 1 is prime.at n=25A003307
- Numbers k that divide the (right) concatenation of all numbers <= k written in base 19 (most significant digit on left).at n=47A029464
- If d,e are consecutive digits of n in base 7, then |d-e|>=5.at n=37A032995
- Fibonacci iteration starting with (1, a(n)) leads to a "nine digits anagram".at n=19A034587
- Decimal expansion of a(n) is given by the first n terms of the periodic sequence with initial period 1,2,3.at n=4A037610
- Positive numbers n such that n is a multiple of (product of digits of n) * (sum of digits of n).at n=12A049102
- Coefficients of the '6th-order' mock theta function rho(q).at n=48A053270
- Coefficients of the '6th-order' mock theta function lambda(q).at n=48A053272
- a(n) = (2*n-1)*(5*n^2-5*n+2)/2.at n=13A063495
- Numbers k such that gcd(d(k^3), d(k)) is not a power of 2.at n=35A069781
- Numbers divisible by the sum of factorials of their digits [A061602(n)] and also terminate in the sum of factorials of their digits.at n=11A071064
- Sum of squares of digits of n is equal to the largest prime factor of n.at n=29A074302
- Numbers divisible by twice the sum of the products of each of their digits, excluding even multiples of 10.at n=32A085446
- Starting with 1, each number is the previous number plus the product of the index number and the sum of the digits of the previous number.at n=37A113904
- Numbers k such that 13*k = A048720(29,k), where A048720 is carryless base-2 multiplication.at n=38A115805
- Integers i such that 10*i XOR 11*i = 21*i.at n=42A115829
- Dividuus numbers: numbers which are divisible by (1) the sum of their digits,(2) the product of their digits,(3) the digital root and (4) the multiplicative digital root.at n=45A118575
- Row sums of A128623.at n=35A128624
- Number of labeled connected bi-point-determining graphs with n vertices (see A129583).at n=6A129585
- a(n) = floor(n/2) * floor(n^2/2).at n=37A131475