[[75]] is not prime (composite): [[3]] * [[5]] * [[5]]

Factor pairs: [[3]] * [[25]], [[5]] * [[15]]

Prime neighborhood: [[67]], [[71]], [[73]], [[75]], [[79]], [[83]], [[89]]

Prime gap: 6 (interval [[73]] to [[79]])

Primes up to 75: [[2]], [[3]], [[5]], [[7]], [[11]], [[13]], [[17]], [[19]], [[23]], [[29]], [[31]], [[37]], [[41]], [[43]], [[47]], [[53]], [[59]], [[61]], [[67]], [[71]], [[73]] (21 total).

[[75]] 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/75]] is closest to [[D2]] at [[75]] Hz (+37 cents).

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

• [[square]]: 5625

• [[square root]]: 8.6603

• [[cube]]: 421875

• [[cube root]]: 4.2172

• [[natural log]] (ln): 4.3175

• [[base-10 log]] (log10): 1.8751

• [[base-2 log]] (log2): 6.2288