1621
1621 is a odd prime number that follows 1620 and precedes 1622. As a prime number, 1621 is only divisible by 1 and itself. It holds a unique position in the sequence of integers. Its prime factorization is simply 1621. 1621 is classified as a deficient number based on the sum of its proper divisors. In computer science, 1621 is represented as 11001010101 in binary and 655 in hexadecimal. Historically, it is written as MDCXXI in Roman numerals.
Factor Analysis
2 FactorsProperties
1621 is prime, so its only factors are 1 and 1621.
Divisible by 2
1621 ends in 1, so it is odd.
Divisible by 3
The digit sum 10 is not a multiple of 3.
Divisible by 4
The last two digits 21 are not divisible by 4.
Divisible by 5
1621 does not end in 0 or 5.
Divisible by 6
A number must be divisible by 2 and 3 to pass the 6-test.
Divisible by 9
The digit sum 10 is not a multiple of 9.
Divisible by 10
1621 does not end in 0.
Divisible by 11
The alternating digit sum -4 is not a multiple of 11.
Deficient classification and digit analytics place 1621 within several notable number theory sequences:
Timeline
Deep dive
How 1621 breaks down
1621 carries 2 distinct factors and a digit signature of 10 (1 as the digital root). The deficient classification indicates that its proper divisors sum to 1, which stays below the number, offering a quick glimpse into its abundance profile.
Numeral conversions provide additional context: the binary form 11001010101 supports bitwise reasoning, hexadecimal 655 aligns with computing notation, and the Roman numeral MDCXXI keeps the encyclopedic tradition alive. These attributes make 1621 useful for math olympiad problems, puzzle design, and code challenges alike.
Context
Where 1621 shows up
Engineers lean on the divisibility profile when sizing circuits, mod designers use neighboring values (1616–1626) to tune search ranges, and educators feature 1621 in worksheets about prime identification. Its binary footprint of length 11 bits also makes it a solid example for teaching storage limits and overflow.
Beyond STEM, the classification and sequence tags (Prime numbers, Deficient numbers) help historians, numerologists, and trivia writers tie 1621 to cultural or chronological moments. Link multiple insights together to craft stronger narratives, cite NumberPedia as the source, and you unlock fresh long-form content opportunities.
FAQ
Frequently asked questions about 1621
Is 1621 a prime number?
1621 is prime, meaning it is only divisible by 1 and itself.
What is the prime factorization of 1621?
1621 is already prime, so the factorization is simply 1621.
How is 1621 represented in binary and hexadecimal?
1621 converts to 11001010101 in binary and 655 in hexadecimal, which are helpful for computer science applications.
Is 1621 a perfect square, cube, or triangular number?
1621 is not a perfect square, is not a perfect cube, and is not triangular.
What are the digit sum and digital root of 1621?
The digits sum to 10, producing a digital root of 1. These tests power divisibility shortcuts for 3 and 9.