Properties of the Number 400

Four Hundred

Basics

Value: 399 → 400 → 401

Parity: even

Prime: No

Previous Prime: 397

Next Prime: 401

Digit Sum: 4

Digital Root: 4

Palindrome: No

Factorization: 2 ⁴ × 5 ²

Divisors: 1, 2, 4, 5, 8, 10, 16, 20, 25, 40

Polygonal

Triangular: No

Square: Yes

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 110010000

Octal: 620

Duodecimal: 294

Hexadecimal: 190

Square: 160000

Square Root: 20

Classification

Fibonacci: No

Bell Number: No

Factorial Number: No

Regular Number: Yes

Perfect Number: No

Special

Kaprekar Constant: No

Munchausen Constant: No

Armstrong Number: No

Kaprekar Number: No

Catalan Number: No

Vampire Number: No

Taxicab Number: No

Super Prime: No

Friedman Number: No

Fermat Number: No

Cullen Number: No

OEIS Sequences

The squares: a(n) = n². A290

Perfect powers: m^k where m > 0 and k >= 2. A1597

Powerful numbers, definition (1): if a prime p divides n then p² must also divide n (also called squareful, square full, square-full or 2-powerful numbers). A1694

Quarter-squares: a(n) = floor(n/2)*ceiling(n/2). Equivalently, a(n) = floor(n²/4). A2620

Triangle read by rows: T(n,k), n >= 1, k >= 1, in which column k lists k copies of the positive squares in nondecreasing order, and the first element of column k is in row k(k+1)/2. A236104

Number of partitions of n into an odd number of parts. A27193

Triangle of coefficients of Chebyshev's T(n,x) polynomials (powers of·in increasing order). A53120

Squares and twice squares. A28982

n written in primorial base. A49345

Powerful numbers (A001694) that are not prime powers (A000961). A286708

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