12090
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 12
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 32
- Divisor Sum
- 32256
- Proper Divisor Sum (Aliquot Sum)
- 20166
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 2880
- Möbius Function
- -1
- Radical
- 12090
- Omega Function (Ω)
- 5
- Little Omega Function (ω)
- 5
Special
- Factorial
- no
- Catalan Number
- no
- Bell Number
- no
- Motzkin Number
- no
- Primorial
- no
Figurate Numbers
- Fibonacci Number
- no
- Triangular Number
- yes
- Perfect Square
- no
- Perfect Cube
- no
- Pentagonal Number
- no
- Hexagonal Number
- yes
- Lucas Number
- no
- Tetrahedral Number
- no
- Pell Number
- no
- Tribonacci Number
- no
- Pronic Number
- no
Recreational
- Happy Number
- yes
- 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
- 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
- yes
- Odd
- no
Appears in sequences
- Number of positive integers <= 2^n of form x^2 + 4 y^2.at n=16A000072
- a(n) = 2*n*(4*n - 1).at n=39A014635
- [ exp(7/8)*n! ].at n=6A030958
- Decimal part of n-th root of a(n) starts with digit 6.at n=18A034083
- Triangular numbers that have some nontrivial permutation of digits which is also triangular.at n=41A034291
- Numerators of continued fraction convergents to sqrt(909).at n=6A042756
- Products of exactly 5 distinct primes.at n=31A046387
- Expansion of series related to Liouville's Last Theorem: g.f. sum_{t>0} (-1)^(t+1) *x^(t*(t+1)/2) / ( (1-x^t)^6 *product_{i=1..t} (1-x^i) ).at n=12A059823
- a(n) = n^4 - (n-1)^4 + (n-2)^4 - ... 0^4.at n=12A062392
- Smallest triangular numbers that contain the digits of n anywhere in their middle.at n=20A062829
- a(1) = 0; for n > 1, a(n) is the square root of the smallest square > a(n-1)^2 with a(n-1)^2 forming its final digits.at n=4A065690
- Smallest triangular number which is a multiple (>1) of the n-th triangular number.at n=29A068084
- Triangular numbers of the form 10*k.at n=30A069498
- Smallest triangular number beginning with the n-th triangular number other than itself.at n=14A072517
- Triangular numbers which are 5-almost primes.at n=30A076579
- Triangular numbers which are also happy numbers (cf. A007770).at n=21A076712
- Triangular numbers whose external digits form a triangular number. Or triangular number whose MSD and LSD form a triangular number.at n=48A077367
- Smallest triangular number > 1 and == 1 (mod prime(n)).at n=36A087397
- Duplicate of A062392.at n=11A088058
- Smallest triangular number greater than n! with the same leading digits as n!.at n=4A096564