41
domain: N
Properties
Digital Properties
- Digit Count
- 2
- Digit Sum
- 5
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 42
- Proper Divisor Sum (Aliquot Sum)
- 1
- 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
- -1
- Radical
- 41
- Omega Function (Ω)
- 1
- Little Omega Function (ω)
- 1
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
- 109
- Smith Number
- no
Classification
- Natural
- yes
- Even
- no
- Odd
- yes
Primality
- Prime
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- yes
- Mersenne Prime
- no
- Sophie Germain Prime
- yes
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 13
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Names
- German
- einundvierzig· ordinal: einundvierzigste
- English
- forty-one· ordinal: forty-first
- Spanish
- cuarenta y uno· ordinal: 41º
- French
- quarante et un· ordinal: quarante et unième
- Italian
- quarantuno· ordinal: 41º
- Latin
- quadraginta unus· ordinal: 41.
- Portuguese
- quarenta e um· ordinal: 41º
Appears in sequences
- Smallest prime power >= n.at n=37A000015
- Smallest prime power >= n.at n=38A000015
- Smallest prime power >= n.at n=39A000015
- Smallest prime power >= n.at n=40A000015
- Mosaic numbers or multiplicative projection of n: if n = Product (p_j^k_j) then a(n) = Product (p_j * k_j).at n=40A000026
- The positive integers. Also called the natural numbers, the whole numbers or the counting numbers, but these terms are ambiguous.at n=40A000027
- Let k = p_1^e_1 p_2^e_2 p_3^e_3 ... be the prime factorization of n. Sequence gives k such that the sum of the numbers of 1's in the binary expansions of e_1, e_2, e_3, ... is odd.at n=19A000028
- Numbers that are not squares (or, the nonsquares).at n=34A000037
- 1-digit numbers arranged in alphabetical order, then the 2-digit numbers arranged in alphabetical order, then the 3-digit numbers, etc.at n=38A000052
- Numbers k such that (2k)^4 + 1 is prime.at n=14A000059
- A Beatty sequence: a(n) = floor(n/(e-2)).at n=29A000062
- -1 + number of partitions of n.at n=10A000065
- Odious numbers: numbers with an odd number of 1's in their binary expansion.at n=20A000069
- Number of positive integers <= 2^n of form x^2 + 4 y^2.at n=7A000072
- a(n) = floor(n^(3/2)).at n=12A000093
- Let A(n) = #{(i,j): i^2 + j^2 <= n}, V(n) = Pi*n, P(n) = A(n) - V(n); sequence gives values of n where |P(n)| sets a new record.at n=7A000099
- Number of partitions into non-integral powers.at n=4A000158
- A Beatty sequence: floor(n*(e-1)).at n=23A000210
- Expansion of e.g.f. exp(x*exp(x)).at n=4A000248
- Remove all factors of 2 from n; or largest odd divisor of n; or odd part of n.at n=40A000265