[[45]] is not prime (composite). Want proof? :)

Full prime factorization: [[3]] * [[3]] * [[5]]

Factor pairs:

[[45]] = [[3]] * [[15]]

[[45]] = [[5]] * [[9]]

Proper divisors: [[3]], [[5]], [[9]], [[15]]

Primes up to 45: [[2]], [[3]], [[5]], [[7]], [[11]], [[13]], [[17]], [[19]], [[23]], [[29]], [[31]], [[37]], [[41]], [[43]].

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

The closest centered hexagonal numbers are [[37]] (index #[[4]]) and [[61]] (index #[[5]]).

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]].

• [[square]]: 2025

• [[square root]]: 6.7082

• [[cube]]: 91125

• [[cube root]]: 3.5569

• [[natural log]] (ln): 3.8067

• [[base-10 log]] (log10): 1.6532

• [[base-2 log]] (log2): 5.4919