69
domain: N
Properties
Digital Properties
- Digit Count
- 2
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 96
- Proper Divisor Sum (Aliquot Sum)
- 27
- 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
- 44
- Möbius Function
- 1
- Radical
- 69
- 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
- 14
- Smith Number
- no
Classification
- Natural
- yes
- Even
- no
- Odd
- yes
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
Names
- German
- neunundsechzig· ordinal: neunundsechzigste
- English
- sixty-nine· ordinal: sixty-ninth
- Spanish
- sesenta y nueve· ordinal: 69º
- French
- soixante-neuf· ordinal: soixante-neufième
- Italian
- sessantanove· ordinal: 69º
- Latin
- sexaginta novem· ordinal: 69.
- Portuguese
- sessenta e nove· ordinal: 69º
Appears in sequences
- Mosaic numbers or multiplicative projection of n: if n = Product (p_j^k_j) then a(n) = Product (p_j * k_j).at n=68A000026
- The positive integers. Also called the natural numbers, the whole numbers or the counting numbers, but these terms are ambiguous.at n=68A000027
- Numbers that are not squares (or, the nonsquares).at n=60A000037
- A Beatty sequence: a(n) = floor(n/(e-2)).at n=49A000062
- Odious numbers: numbers with an odd number of 1's in their binary expansion.at n=34A000069
- Lower Wythoff sequence (a Beatty sequence): a(n) = floor(n*phi), where phi = (1+sqrt(5))/2 = A001622.at n=42A000201
- a(8i+j) = 13i + a(j), where 1<=j<=8.at n=42A000202
- 3rd power of rooted tree enumerator; number of linear forests of 3 rooted trees.at n=4A000242
- Remove all factors of 2 from n; or largest odd divisor of n; or odd part of n.at n=68A000265
- 3*n - 2*floor(sqrt(4*n+5)) + 5.at n=28A000277
- Number of permutations of [n] in which the longest increasing run has length 2.at n=4A000303
- Let A(n) = #{(i,j): i^2 + j^2 <= n}, V(n) = Pi*n, P(n) = A(n) - V(n); A000099 gives values of n where |P(n)| sets a new record; sequence gives A(A000099(n)).at n=4A000323
- Let A(n) = #{(i,j): i^2 + j^2 <= n}, V(n) = Pi*n, P(n) = A(n) - V(n); A000099 gives values of n where |P(n)| sets a new record; sequence gives A(A000099(n)).at n=5A000323
- Sums of three squares: numbers of the form x^2 + y^2 + z^2.at n=59A000378
- Numbers where total number of 1-bits in the exponents of their prime factorization is even; a 2-way classification of integers: complement of A000028.at n=36A000379
- Numbers of form x^2 + y^2 + 7z^2.at n=57A000394
- Numbers of form x^2 + y^2 + 2*z^2.at n=64A000401
- Numbers that are the sum of three nonzero squares.at n=42A000408
- Numbers that are the sum of 4 nonzero squares.at n=53A000414
- Numbers that are the sum of 3 but no fewer nonzero squares.at n=27A000419