Properties of the Number 1644

One Thousand Six Hundred Forty-Four

Basics

Value: 1643 → 1644 → 1645

Parity: even

Prime: No

Previous Prime: 1637

Next Prime: 1657

Digit Sum: 15

Digital Root: 6

Palindrome: No

Factorization: 2 ² × 3 × 137

Divisors: 1, 2, 3, 4, 6, 12, 137, 274, 411, 548

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 11001101100

Octal: 3154

Duodecimal: B50

Hexadecimal: 66c

Square: 2702736

Square Root: 40.54626986542659

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

Sums of twin prime pairs. A54735

Sum of first n nonprimes. A51349

Numbers m such that there are precisely 12 groups of order m. A249555

a(n) = floor(n*φ⁸), where φ is the golden ratio, A001622. A4923

Convolution triangle of A001045(n+1) (generalized (1,2)-Fibonacci), n>=0. A73370

Numbers k whose largest divisor <= sqrt(k) equals 12. A162532

a(n) = (3ⁿ⁺¹ + 2·n + 1)/4. A47926

Total number of ON cells at stage n of two-dimensional 5-neighbor outer totalistic cellular automaton defined by "Rule 452". A246316

Number of integer partitions of n whose distinct parts have integer mean. A360241

Initial values for iteration of A063919(x) function such that iteration ends in a 2-cycle, i.e., "attracted" by unitary amicable numbers, A063991. A97037