75
domain: N
Properties
Digital Properties
- Digit Count
- 2
- Digit Sum
- 12
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 124
- Proper Divisor Sum (Aliquot Sum)
- 49
- 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
- 40
- Möbius Function
- 0
- Radical
- 15
- Omega Function (Ω)
- 3
- 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
- no
- Squarefree Number
- no
- 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
- yes
- Carmichael Number
- no
Names
- German
- fünfundsiebzig· ordinal: fünfundsiebzigste
- English
- seventy-five· ordinal: seventy-fifth
- Spanish
- setenta y cinco· ordinal: 75º
- French
- soixante-quinze· ordinal: soixante-quinzième
- Italian
- settantacinque· ordinal: 75º
- Latin
- septuaginta quinque· ordinal: 75.
- Portuguese
- setenta e cinco· ordinal: 75º
Appears in sequences
- The positive integers. Also called the natural numbers, the whole numbers or the counting numbers, but these terms are ambiguous.at n=74A000027
- Numbers that are not squares (or, the nonsquares).at n=66A000037
- 1-digit numbers arranged in alphabetical order, then the 2-digit numbers arranged in alphabetical order, then the 3-digit numbers, etc.at n=58A000052
- A Beatty sequence: a(n) = floor(n/(e-2)).at n=53A000062
- Positive zeros of Bessel function of order 0 rounded to nearest integer.at n=23A000134
- A Beatty sequence: floor(n*(e-1)).at n=43A000210
- a(n) = floor(n^2/3).at n=15A000212
- Number of trees with n nodes, 2 of which are labeled.at n=4A000243
- Remove all factors of 2 from n; or largest odd divisor of n; or odd part of n.at n=74A000265
- Expansion of e.g.f. exp(-x^2/2) / (1-x).at n=5A000266
- Nearest integer to b(n), where b(n) = tan(b(n-1)), b(0) = 1.at n=2A000329
- Expansion of x^3*(5-2*x)*(1-x^3)/(1-x)^4.at n=3A000338
- a(n) = 5*binomial(2n, n-2)/(n+3).at n=3A000344
- Sums of three squares: numbers of the form x^2 + y^2 + z^2.at n=64A000378
- 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=38A000379
- Numbers of form x^2 + y^2 + 2*z^2.at n=70A000401
- Numbers that are the sum of three nonzero squares.at n=47A000408
- Numbers that are the sum of 4 nonzero squares.at n=59A000414
- Numbers that are the sum of 3 but no fewer nonzero squares.at n=29A000419
- Number of nonnegative solutions of x^2 + y^2 = z in first n shells.at n=37A000592