[[67]] is prime.

Prime neighborhood: [[53]], [[59]], [[61]], [[67]], [[71]], [[73]], [[79]]

Special relations: cousin prime with [[71]], sexy prime with [[61]].

Primes up to 67: [[2]], [[3]], [[5]], [[7]], [[11]], [[13]], [[17]], [[19]], [[23]], [[29]], [[31]], [[37]], [[41]], [[43]], [[47]], [[53]], [[59]], [[61]], [[67]] (19 total).

[[67]] is not a centered hexagonal number.

The closest centered hexagonal numbers are [[61]] (index # [[5]]) and [[91]] (index # [[6]]).

First 20 centered hexagonal numbers: [[1]], [[7]], [[19]], [[37]], [[61]], [[91]], [[127]], [[169]], [[217]], [[271]], [[331]], [[397]], [[469]], [[547]], [[631]], [[721]], [[817]], [[919]], [[1027]], [[1141]].

[[hz/67]] is closest to [[C2]] at [[67]] Hz (+42 cents).

Note class: [[C]], Octave: [[octave/2]].

• [[square]]: 4489

• [[square root]]: 8.1854

• [[cube]]: 300763

• [[cube root]]: 4.0615

• [[natural log]] (ln): 4.2047

• [[base-10 log]] (log10): 1.8261

• [[base-2 log]] (log2): 6.0661