400
domain: N
Properties
Digital Properties
- Digit Count
- 3
- Digit Sum
- 4
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 15
- Divisor Sum
- 961
- Proper Divisor Sum (Aliquot Sum)
- 561
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 160
- Möbius Function
- 0
- Radical
- 10
- Omega Function (Ω)
- 6
- 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
- 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
- no
- Harshad Number
- yes
- Narcissistic Number
- no
- Collatz Steps
- 27
- Smith Number
- no
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
- yes
- Achilles Number
- no
- Perfect Power
- yes
- Smooth Number
- yes
- Carmichael Number
- no
Classification
- Even
- yes
- Odd
- no
Names
- German
- vierhundert· ordinal: vierhundertste
- English
- four hundred· ordinal: four hundredth
- Spanish
- cuatrocientos· ordinal: 400º
- French
- quatre cents· ordinal: quatre centsième
- Italian
- quattrocento· ordinal: 400º
- Latin
- quadringenti· ordinal: 400.
- Portuguese
- quatrocentos· ordinal: 400º
Appears in sequences
- Number of ways of writing n as a sum of 5 squares.at n=12A000132
- Restricted permutations.at n=7A000382
- n followed by n^2.at n=39A000463
- Numbers that are the sum of 2 squares but not sum of 3 nonzero squares.at n=28A000549
- Numbers beginning with letter 'f' in English.at n=24A000867
- Numbers n such that the sum of the squares of n consecutive positive odd numbers x^2 + (x+2)^2 + ... + (x+2n-2)^2 = k^2 for some integer k. The least values of x and k for each n are in A056131 and A056132, respectively.at n=29A001033
- Numbers k such that k / (sum of digits of k) is a square.at n=25A001102
- A self-generating sequence: a(1)=1, a(2)=2, a(n+1) chosen so that a(n+1)-a(n-1) is the first number not obtainable as a(j)-a(i) for 1<=i<j<=n.at n=24A001149
- Squares of tetrahedral numbers: a(n) = binomial(n+3,n)^2.at n=3A001249
- Squares of numbers of rooted trees.at n=5A001257
- Perfect powers: m^k where m > 0 and k >= 2.at n=27A001597
- Powerful numbers, definition (1): if a prime p divides n then p^2 must also divide n (also called squareful, square full, square-full or 2-powerful numbers).at n=32A001694
- Squares written in base 5.at n=10A001740
- Squares written in base 6.at n=12A001741
- Numbers n such that every digit contains a loop (version 2).at n=25A001744
- Negated coefficients of Chebyshev T polynomials: [x^n](-T(n+6, x)), n >= 0.at n=4A001794
- The coding-theoretic function A(n,4,3).at n=49A001839
- Number of divisors of n-th highly composite number.at n=44A002183
- Absolute value of Glaisher's beta'(2n+1).at n=32A002291
- Squares written in base 7.at n=13A002440