11111
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 5
- Digital Root
- 5
- Palindromic Number
- yes
- Repdigit
- yes
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 11424
- Proper Divisor Sum (Aliquot Sum)
- 313
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 10800
- Möbius Function
- 1
- Radical
- 11111
- 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
- 55
- 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
- Unary representation of natural numbers.at n=4A000042
- Strobogrammatic numbers: the same upside down.at n=43A000787
- Deceptive nonprimes: composite numbers k that divide the repunit R_{k-1}.at n=21A000864
- 5 in base 10-n.at n=9A001735
- a(n) = n^2 written in base 3.at n=11A001738
- Repunits: (10^n - 1)/9. Often denoted by R_n.at n=5A002275
- Numbers whose square is a palindrome.at n=24A002778
- Least positive multiple of n written in base 3 using only 0 and 1.at n=10A004283
- Least positive multiple of n written in base 4 using only 0 and 1.at n=30A004284
- Least positive multiple of n written in base 4 using only 0 and 1.at n=10A004284
- Least positive multiple of n written in base 5 using only 0 and 1.at n=10A004285
- Least positive multiple of n written in base 6 using only 0 and 1.at n=4A004286
- Least positive multiple of n written in base 8 using only 0 and 1.at n=30A004288
- Least positive multiple of n written in base 9 using only 0 and 1.at n=10A004289
- Primes written in base 2.at n=10A004676
- Pseudoprimes to base 10.at n=32A005939
- Numbers with mirror symmetry about middle.at n=21A006072
- The binary numbers (or binary words, or binary vectors, or binary expansion of n): numbers written in base 2.at n=31A007088
- Numbers that contain only 1's and 2's. Nonempty binary strings of length n in lexicographic order.at n=30A007931
- a(0) = 1, a(n) = 21*n^2 + 2 for n>0.at n=23A010011