555 (number)

Last updated
← 554 555 556 →
Cardinal five hundred fifty-five
Ordinal 555th
(five hundred fifty-fifth)
Factorization 3 × 5 × 37
Greek numeral ΦΝΕ´
Roman numeral DLV, dlv
Binary 10001010112
Ternary 2021203
Senary 23236
Octal 10538
Duodecimal 3A312
Hexadecimal 22B16

555 (five hundred [and] fifty-five) is the natural number following 554 and preceding 556.

Contents

In mathematics

555 is a sphenic number. In base 10, it is a repdigit, and because it is divisible by the sum of its digits, it is a Harshad number. It is also a Harshad number in binary, base 11, base 13 and hexadecimal.

555 is a Harshad number as 555 ÷ (5+5+5) is 555 ÷ 15 is 37. [1] Also, 555 is unique because it is not just a multiple of 5+5+5 (15) but that 15 is divisible by its triangular order.

It is the sum of the first triplet of three-digit permutable primes in decimal:

.

It is the twenty-sixth number such that its Euler totient (288) is equal to the totient value of its sum-of-divisors: . [2]

References

  1. ↑ "Properties of number 555". www.numbersaplenty.com. Archived from the original on 2024-12-06. Retrieved 2025-04-03. It is a Harshad number since it is a multiple of its sum of digits (15), and also a Moran number because the ratio is a prime number: 37 = 555 / (5 + 5 + 5).
  2. ↑ Sloane, N. J. A. (ed.). "SequenceA006872(Numbers k such that phi(k) is phi(sigma(k)).)". The On-Line Encyclopedia of Integer Sequences . OEIS Foundation. Retrieved 2023-08-31.


This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.