← 29 30 31 →
Cardinalthirty
Ordinal30th
(thirtieth)
Factorization2 × 3 × 5
Divisors1, 2, 3, 5, 6, 10, 15, 30
Greek numeralΛ´
Roman numeralXXX
Binary111102
Ternary10103
Senary506
Octal368
Duodecimal2612
Hexadecimal1E16

30 (thirty) is the natural number following 29 and preceding 31.

In mathematics

30 is a square pyramidal number.

30 is an even, composite, pronic number. With 2, 3, and 5 as its prime factors, it is a regular number and the first sphenic number, the smallest of the form , where r is a prime greater than 3. It has an aliquot sum of 42, which is the second sphenic number.

It is also:

Furthermore,

In a group G, such that , where p does not divide m, and has a subgroup of order , 30 is the only number less than 60 that is neither a prime nor of the aforementioned form. Therefore, 30 is the only candidate for the order of a simple group less than 60, in which one needs other methods to specifically reject to eventually deduce said order.[citation needed]

The SI prefix for 1030 is Quetta- (Q), and for 10−30 (i.e., the reciprocal of 1030) quecto (q). These numbers are the largest and smallest number to receive an SI prefix to date.

In science

Astronomy

In other fields

Thirty is:

History and literature

Sports

Music

See also: 30 (disambiguation) § music

See also

References

  1. ^ "Sloane's A005835 : Pseudoperfect (or semiperfect) numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 31 May 2016.
  2. ^ "Sloane's A002110 : Primorial numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 31 May 2016.
  3. ^ "Sloane's A005349 : Niven (or Harshad) numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 31 May 2016.
  4. ^ "Sloane's A000330 : Square pyramidal numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 31 May 2016.
  5. ^ Barnes, Richard (June 2006). "Report of the 7 July Review Committee" (PDF). BBC News. Retrieved 18 December 2011.