Properties of the Number 21109

Twenty-One Thousand One Hundred Nine

Basics

Value: 21108 → 21109 → 21110

Parity: odd

Prime: No

Previous Prime: 21107

Next Prime: 21121

Digit Sum: 13

Digital Root: 4

Palindrome: No

Factorization: 11 × 19 × 101

Divisors: 1, 11, 19, 101, 209, 1111, 1919, 21109

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101001001110101

Octal: 51165

Duodecimal: 10271

Hexadecimal: 5275

Square: 445589881

Square Root: 145.28936643815334

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

Fundamental discriminants d uniquely characterizing all complex biquadratic fields Q(sqrt(-3),sqrt(d)) which have 3-class group of type (3,3) and second 3-class group isomorphic to either SmallGroup(2187,247)-#1;5 or SmallGroup(2187,247)-#1;9. A250242

Number of partitions of n with rank a multiple of 3. A328988

4-white numbers: partition digits of n⁴ into blocks of 4 starting at right; sum of these 4-digit numbers equals n. A37044

a(n) = A169780(2ⁿ). A169781

a(n) is the sum of squares of the first n positive integers congruent to 2 mod 3. A24394

Composite numbers n such that the distinct digits in n and the distinct digits in the proper divisors of n are the same. A237713

Numbers k such that the set of all the decimal digits of k is the same as the set of all the decimal digits of the proper divisors of k. A282755

a(n) = (1/9)*(-1+10ⁿ)*(4·n+3). A95752

Decimal expansion of 1/105. A21109