555 (Number)

	List of numbers — Integers ← 0 100 200 300 400 500 600 700 800 900 →
Cardinal	five hundred fifty-five
Ordinal	555th; (five hundred fifty-fifth)
Factorization	3 × 5 × 37
Greek numeral	ΦΝΕ´
Roman numeral	DLV
Binary	10001010112
Ternary	2021203
Quaternary	202234
Quinary	42105
Senary	23236
Octal	10538
Duodecimal	3A312
Hexadecimal	22B16
Vigesimal	17F20
Base 36	FF36

Short description: Natural number

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

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.

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

[math]\displaystyle{ 113 + 131 + 311 = 555 }[/math].

It is the twenty-sixth number such that its Euler totient (288) is equal to the totient value of its sum-of-divisors: [math]\displaystyle{ \varphi(555) = \varphi(\sigma(555)) }[/math].^[1]

References

↑ Sloane, N. J. A., ed. "Sequence A006872 (Numbers k such that phi(k) is phi(sigma(k)).)". OEIS Foundation. https://oeis.org/A006872. Retrieved 2023-08-31.

External links

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Original source: https://en.wikipedia.org/wiki/555 (number). Read more

[1] Sloane, N. J. A., ed. "Sequence A006872 (Numbers k such that phi(k) is phi(sigma(k)).)". OEIS Foundation. https://oeis.org/A006872. Retrieved 2023-08-31.