2542
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 4032
- Proper Divisor Sum (Aliquot Sum)
- 1490
- 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
- 1200
- Möbius Function
- -1
- Radical
- 2542
- Omega Function (Ω)
- 3
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 32
- 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
- Squares written in base 7.at n=30A002440
- Second pentagonal numbers: a(n) = n*(3*n + 1)/2.at n=41A005449
- Optimal cost of search tree for searching an ordered array of n elements with cost k of probing element k.at n=33A007077
- For any circular arrangement of 0..n-1, let S = sum of squares of every sum of two contiguous numbers; then a(n) = # of distinct values of S.at n=24A007773
- Coordination sequence T3 for Zeolite Code MEI.at n=37A008148
- Coordination sequence T6 for Zeolite Code MFI.at n=32A008169
- Coordination sequence T4 for Zeolite Code VNI.at n=31A009910
- Numbers whose base-3 representation is the juxtaposition of two identical strings.at n=30A020331
- Numbers whose base-9 representation is the juxtaposition of two identical strings.at n=30A020337
- Convolution of natural numbers with composite numbers.at n=18A023539
- Numbers with exactly 6 1's in their ternary expansion.at n=17A023697
- Every prefix prime in base 9 (written in base 9).at n=28A024769
- Least m such that if r and s in {1/1, 1/3, 1/6,..., 1/C(n+1,2)} satisfy r < s, then r < k/m < s for some integer k.at n=23A024826
- 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 50.at n=3A031548
- Numbers whose set of base-9 digits is {3,4}.at n=19A032833
- Second pentagonal numbers with odd index: a(n) = (2*n-1)*(3*n-1).at n=21A033568
- Numbers of the form k*(k+1)/6 for k = 2 or 3 modulo 6.at n=41A036499
- Sums of 6 distinct powers of 3.at n=10A038468
- Numbers k such that 0 and 1 occur juxtaposed in the base-11 representation of k but not of k+1.at n=37A044041
- Numbers n such that string 4,2 occurs in the base 10 representation of n but not of n-1.at n=28A044374