In Mathematics
133 is an n whose divisors (excluding n itself) added up divide φ(n). It is an octagonal number and a Harshad number. It is also a happy number.
133 is a repdigit in base 11 (111) and base 18 (77), whilst in base 20 it is a cyclic number formed from the reciprocal of the number three.
133 is a semiprime: a product of two prime numbers, namely 7 and 19. Since those prime factors are Gaussian primes, this means that 133 is a Blum integer.
Read more about this topic: 133 (number)
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—Simone Weil (1909–1943)
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