# 133 (number)

 ← 132 133 134 →
Cardinalone hundred thirty-three
Ordinal133rd
(one hundred thirty-third)
Factorization7 × 19
Divisors1, 7, 19, 133
Greek numeralΡΛΓ´
Roman numeralCXXXIII
Binary100001012
Ternary112213
Quaternary20114
Quinary10135
Senary3416
Octal2058
DuodecimalB112
Vigesimal6D20
Base 363P36

133 (one hundred [and] thirty-three) is a natural number. It is after 132 and before 134.

## In mathematics

The sum of 133's proper divisors is equal to φ(n).

133 is an octagonal number,[1] a Harshad number[2] and a happy number.[3]

In base 11(111) and base 18(77), 133 is a repdigit(a natural number that has only one type of digit).

133 is a semiprime number number(a product of 7 and 19). 7 and 19 are both Gaussian primes. This makes that 133 is a Blum integer

133 is also:

## References

1. "Sloane's A000567 : Octagonal numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-27.
2. "Sloane's A005349 : Niven (or Harshad) numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-27.
3. "Sloane's A007770 : Happy numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-27.
4. Porter, Darwin; Danforth Prince (2009). Frommer's Austria. Hoboken, New Jersey: Frommer's. p. 482. ISBN 978-0-470-39897-5.