• [[square]]: 441

• [[square root]]: 4.5826

• [[cube]]: 9261

• [[cube root]]: 2.7589

• [[natural log]] (ln): 3.0445

• [[base-10 log]] (log10): 1.3222

• [[base-2 log]] (log2): 4.3923

[[21]] is not prime. Want proof? :)

[[21]] is composite: 3 * 7.

Primes up to 21: 2, 3, 5, 7, 11, 13, 17, 19.

hex(1) is 1.

hex(2) is 7.

hex(3) is 19.

hex(4) is 37.

hex(5) is 61.

hex(6) is 91.

hex(7) is 127.

hex(8) is 169.

hex(9) is 217.

hex(10) is 271.

hex(11) is 331.

hex(12) is 397.

hex(13) is 469.

hex(14) is 547.

hex(15) is 631.

hex(16) is 721.

hex(17) is 817.

hex(18) is 919.

hex(19) is 1027.

hex(20) is 1141.

hex(21) is 1261.