188
Jump to navigation
Jump to search
Number
$188$ (one hundred and eighty-eight) is:
- $2^2 \times 47$
- The $10$th untouchable number after $2$, $5$, $52$, $88$, $96$, $120$, $124$, $146$, $162$.
- The $27$th nontotient:
- $\nexists m \in \Z_{>0}: \map \phi m = 188$
- where $\map \phi m$ denotes the Euler $\phi$ function
- The $29$th happy number after $1$, $7$, $10$, $13$, $19$, $23$, $\ldots$, $91$, $94$, $97$, $100$, $103$, $109$, $129$, $130$, $133$, $139$, $167$, $176$:
- $188 \to 1^2 + 8^2 + 8^2 = 1 + 64 + 64 = 129 \to 1^2 + 2^2 + 9^2 = 1 + 4 + 81 = 86 \to 8^2 + 6^2 = 64 + 36 = 100 \to 1^2 + 0^2 + 0^2 = 1$
Also see
- Previous ... Next: Untouchable Number
- Previous ... Next: Happy Number
- Previous ... Next: Nontotient
Sources
- 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $188$