1945
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 2340
- Proper Divisor Sum (Aliquot Sum)
- 395
- 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
- 1552
- Möbius Function
- 1
- Radical
- 1945
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 37
- 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
- no
- Odd
- yes
Appears in sequences
- A self-generating sequence: a(1)=1, a(2)=2, a(n+1) chosen so that a(n+1)-a(n-1) is the first number not obtainable as a(j)-a(i) for 1<=i<j<=n.at n=49A001149
- Numbers that are the sum of 3 nonnegative cubes in more than 1 way.at n=20A001239
- Number of partitions of n into at most 6 parts.at n=34A001402
- Number of partitions of n into parts 2, 3, 4, 5, 6, 7.at n=52A001996
- a(n) = floor(n(n+2)(2n+1)/8).at n=19A002717
- a(n) = n^2 + prime(n).at n=41A004232
- a(n) = floor(1000*log(n)).at n=6A004240
- Number of partitions of n into 3 or more parts.at n=24A004250
- a(n) = least integer m > a(n-1) such that m - a(n-1) != a(j) - a(k) for all j, k less than n; a(1) = 1, a(2) = 2.at n=42A004978
- Coordination sequence T10 for Zeolite Code MFI.at n=28A008162
- Numbers that are the sum of 3 positive cubes in more than one way.at n=12A008917
- Coordination sequence T1 for Zeolite Code -CLO.at n=39A009850
- Coordination sequence T1 for Zeolite Code VET.at n=27A009902
- Expansion of 1/((1-4x)(1-5x)(1-8x)).at n=3A018250
- Numbers k such that the continued fraction for sqrt(k) has period 26.at n=44A020365
- Fibonacci sequence beginning 3, 20.at n=11A022129
- Positive integers which apparently never result in a palindrome under repeated applications of the function A056964(x) = x + (x with digits reversed).at n=23A023108
- Convolution of Lucas numbers and A001950.at n=9A023622
- Least m such that if r and s in {1/3, 1/6, 1/9, ..., 1/3n} satisfy r < s, then r < k/m < (k+1)/m < s for some integer k.at n=19A024838
- Numbers that are the sum of 3 distinct positive cubes in 2 or more ways.at n=8A024974