2122
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 7
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 3186
- Proper Divisor Sum (Aliquot Sum)
- 1064
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 1060
- Möbius Function
- 1
- Radical
- 2122
- Omega Function (Ω)
- 2
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 125
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- Primes in ternary.at n=19A001363
- a(n) = n concatenated with n + 1.at n=20A001704
- Oscillates under partition transform.at n=43A007212
- Numbers that contain only 1's and 2's. Nonempty binary strings of length n in lexicographic order.at n=25A007931
- Coordination sequence T1 for Zeolite Code AFY.at n=38A008029
- Coordination sequence T2 for Zeolite Code LTN.at n=32A008141
- Coordination sequence T1 for Zeolite Code NAT.at n=31A008203
- Expansion of (1+x)/((1-x)*(1-x^2)*(1-x^3)*(1-x^4)).at n=49A008762
- Coordination sequence T2 for Zeolite Code -PAR.at n=33A009856
- Coordination sequence T4 for Zeolite Code RSN.at n=30A009888
- Coordination sequence T2 for Zeolite Code VET.at n=28A009903
- Numbers k such that the k-th Euclid number A006862(k) = 1 + (Product of first k primes) is prime.at n=16A014545
- Expansion of 1/(1-x^8-x^9-x^10-x^11-x^12-x^13-x^14-x^15).at n=53A017873
- Numbers k such that the continued fraction for sqrt(k) has period 31.at n=3A020370
- n written in fractional base 3/2.at n=14A024629
- Every prefix prime in base 3 (written in base 3).at n=3A024763
- Every prefix prime in base 9 (written in base 9).at n=25A024769
- Position of numbers of form 3*n^2 in A025060 (numbers of form j*k + k*i + i*j, where 1 <=i < j < k).at n=23A025064
- a(n) = position of the n-th n in A026409.at n=42A026412
- Sequence satisfies T^2(a)=a, where T is defined below.at n=43A027595