214

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Number

$214$ (two hundred and fourteen) is:

$2 \times 107$

The $7$th non-square positive integer which cannot be expressed as the sum of a square and a prime:

$10$, $34$, $58$, $85$, $91$, $130$, $214$, $\ldots$

The $12$th number after $1$, $3$, $22$, $66$, $70$, $81$, $94$, $115$, $119$, $170$, $210$ whose divisor sum is square:

$\map {\sigma_1} {214} = 324 = 18^2$

The $13$th positive integer which cannot be expressed as the sum of a square and a prime:

$1$, $10$, $25$, $34$, $58$, $64$, $85$, $91$, $121$, $130$, $169$, $196$, $214$, $\ldots$

The $31$st nontotient:

$\nexists m \in \Z_{>0}: \map \phi m = 214$

where $\map \phi m$ denotes the Euler $\phi$ function

Also see

• Previous  ... Next: Non-Square Positive Integers not Sum of Square and Prime
• Previous  ... Next: Numbers not Sum of Square and Prime
• Previous  ... Next: Nontotient
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