Properties of the Number 1220

One Thousand Two Hundred Twenty

Basics

Value: 1219 → 1220 → 1221

Parity: even

Prime: No

Previous Prime: 1217

Next Prime: 1223

Digit Sum: 5

Digital Root: 5

Palindrome: No

Factorization: 2 ² × 5 × 61

Divisors: 1, 2, 4, 5, 10, 20, 61, 122, 244, 305

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

Today's Target

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Representations

Binary: 10011000100

Octal: 2304

Duodecimal: 858

Hexadecimal: 4c4

Square: 1488400

Square Root: 34.92849839314596

Classification

Fibonacci: No

Bell Number: No

Factorial Number: No

Regular Number: No

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

a(n) = sigma₂(n): sum of squares of divisors of n. A1157

Integers written in factorial base. A7623

Number of integer partitions of n with distinct differences between successive parts. A325325

n written in primorial base. A49345

Number of binary vectors of length n containing no singletons. A6355

a(n) = ∑_d∣n (-1)^d-1*d². A321543

Numbers k such that 3^k + 2 is prime. A51783

Number of base 4 n-digit numbers with adjacent digits differing by one or less. A126358

Triangular numbers plus quarter squares: n*(n+1)/2 + floor(n²/4) (i.e., A000217(n) + A002620(n)). A6578

Layer counting sequence for hyperbolic tessellation by cuspidal triangles of angles (π/3,π/3,0) (this is the classical modular tessellation). A54886