1857
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 2480
- Proper Divisor Sum (Aliquot Sum)
- 623
- 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
- 1236
- Möbius Function
- 1
- Radical
- 1857
- 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
- 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
- Truncated square numbers: 7*n^2 + 4*n + 1.at n=16A005892
- Year of birth of n-th President of U.S.A.at n=26A008745
- Coordination sequence T3 for Zeolite Code -WEN.at n=31A009864
- sec(sinh(x)*exp(x))=1+1/2!*x^2+6/3!*x^3+33/4!*x^4+220/5!*x^5...at n=6A012522
- Numbers k such that the continued fraction for sqrt(k) has period 38.at n=13A020377
- Positive integers which apparently never result in a palindrome under repeated applications of the function A056964(x) = x + (x with digits reversed).at n=22A023108
- Convolution of (F(2), F(3), F(4), ...) and primes.at n=10A023657
- a(n) = position of n^3 + (n+1)^3 in A024670 (distinct sums of cubes of distinct positive integers).at n=51A024674
- a(n) = position of 3*n^2 in sequence A025051 (numbers of form j*k + k*i + i*j, without repetitions, where 1 <= i <= j <= k).at n=24A025056
- Coordination sequence T2 for Zeolite Code SAT.at n=31A027374
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 28.at n=17A031526
- Lucky numbers with size of gaps equal to 12 (lower terms).at n=22A031894
- Lucky numbers with size of gaps equal to 18 (upper terms).at n=11A031901
- Lucky numbers ending with digit 7.at n=47A032588
- Lucky numbers indexed by the lucky numbers (Lucky numbers with lucky number subscripts).at n=48A032639
- Number of partitions of n with equal nonzero number of parts congruent to each of 0, 1 and 3 (mod 5).at n=47A035583
- The sequence e, given that c is a left shift by one place of b.at n=50A041003
- Numbers k such that 5 and 7 occur juxtaposed in the base-10 representation of k but not of k-1.at n=36A043252
- Numbers having three 3's in base 6.at n=22A043383
- Numbers k such that 5 and 7 occur juxtaposed in the base-10 representation of k but not of k+1.at n=36A044032