94
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Number
$94$ (ninety-four) is:
- $2 \times 47$
- The $3$rd even integer after $2$, $4$ that cannot be expressed as the sum of $2$ prime numbers which are each one of a pair of twin primes
- The $6$th Smith number after $4$, $22$, $27$, $58$, $85$:
- $9 + 4 = 2 + 4 + 7 = 13$
- The $7$th number after $1$, $3$, $22$, $66$, $70$, $81$ whose divisor sum is square:
-
- $\map {\sigma_1} {94} = 144 = 12^2$
- The $11$th integer $m$ such that $m! - 1$ (its factorial minus $1$) is prime:
- $3$, $4$, $6$, $7$, $12$, $14$, $30$, $32$, $33$, $38$, $94$
- The $12$th nontotient after $14$, $26$, $34$, $38$, $50$, $62$, $68$, $74$, $76$, $86$, $90$:
- $\nexists m \in \Z_{>0}: \map \phi m = 94$
- where $\map \phi m$ denotes the Euler $\phi$ function
- The $18$th happy number after $1$, $7$, $10$, $13$, $19$, $23$, $28$, $31$, $32$, $44$, $49$, $68$, $70$, $79$, $82$, $86$, $91$:
- $94 \to 9^2 + 4^2 = 81 + 16 = 97 \to 9^2 + 7^2 = 81 + 49 = 130 \to 1^2 + 3^2 + 0^2 = 1 + 9 + 0 = 10 \to 1^2 + 0^2 = 1$
- The $32$nd semiprime:
- $94 = 2 \times 47$
- The $46$th positive integer after $2$, $3$, $4$, $7$, $8$, $\ldots$, $61$, $65$, $66$, $67$, $72$, $77$, $80$, $81$, $84$, $89$ which cannot be expressed as the sum of distinct pentagonal numbers
Also see
- Previous ... Next: Even Integers not Sum of 2 Twin Primes
- Previous ... Next: Sequence of Integers whose Factorial minus 1 is Prime
- Previous ... Next: Numbers whose Divisor Sum is Square
- Previous ... Next: Smith Number
- Previous ... Next: Numbers not Expressible as Sum of Distinct Pentagonal Numbers
- Previous ... Next: Nontotient
- Previous ... Next: Happy Number
- Previous ... Next: Semiprime Number
Sources
- 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $94$
- 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $94$