49
domain: N
Properties
Digital Properties
- Digit Count
- 2
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 3
- Divisor Sum
- 57
- Proper Divisor Sum (Aliquot Sum)
- 8
- 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
- 42
- Möbius Function
- 0
- Radical
- 7
- Omega Function (Ω)
- 2
- 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
- yes
- 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
- 24
- Smith Number
- no
Classification
- Natural
- yes
- Even
- no
- Odd
- yes
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- Squarefree Number
- no
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- yes
- Achilles Number
- no
- Perfect Power
- yes
- Smooth Number
- no
- Carmichael Number
- no
Names
- German
- neunundvierzig· ordinal: neunundvierzigste
- English
- forty-nine· ordinal: forty-ninth
- Spanish
- cuarenta y nueve· ordinal: 49º
- French
- quarante-neuf· ordinal: quarante-neufième
- Italian
- quarantanove· ordinal: 49º
- Latin
- quadraginta novem· ordinal: 49.
- Portuguese
- quarenta e nove· ordinal: 49º
Appears in sequences
- Number of ways of making change for n cents using coins of 1, 2, 5, 10 cents.at n=22A000008
- Smallest prime power >= n.at n=47A000015
- Smallest prime power >= n.at n=48A000015
- The positive integers. Also called the natural numbers, the whole numbers or the counting numbers, but these terms are ambiguous.at n=48A000027
- 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=23A000028
- 1-digit numbers arranged in alphabetical order, then the 2-digit numbers arranged in alphabetical order, then the 3-digit numbers, etc.at n=37A000052
- Odious numbers: numbers with an odd number of 1's in their binary expansion.at n=24A000069
- Positive zeros of Bessel function of order 0 rounded to nearest integer.at n=15A000134
- Nearest integer to modified Bessel function K_n(2).at n=6A000167
- A Beatty sequence: floor(n*(e-1)).at n=28A000210
- a(n) = a(n-1) + a(n-2) - 2, a(0) = 4, a(1) = 3.at n=8A000211
- Remove all factors of 2 from n; or largest odd divisor of n; or odd part of n.at n=48A000265
- Tetranacci numbers: a(n) = a(n-1) + a(n-2) + a(n-3) + a(n-4) with a(0) = a(1) = a(2) = a(3) = 1.at n=8A000288
- A nonlinear recurrence: a(0) = 1, a(1) = 5, a(n) = a(n-1)^2 - 4*a(n-1) + 4 for n>1.at n=3A000324
- Number of points of norm <= n^2 in square lattice.at n=4A000328
- a(n) = (n-1)*2^n + 1.at n=4A000337
- Numbers m such that Fibonacci(m) ends with m.at n=6A000350
- Sums of three squares: numbers of the form x^2 + y^2 + z^2.at n=42A000378
- Numbers of form x^2 + y^2 + 7z^2.at n=40A000394
- Numbers of form x^2 + 2y^2 + 2yz + 4z^2.at n=44A000398