147

147 = 3 x 7².

147 is the number of one-sided 6-polyhexes.

147 = 14² - 7² = (14 + 7)7.

147(14 + 7) = 14³ + 7³ = 3087.

147 is 300 in base 7, 77 in base 20, and 70 in base 21. It is 2103 in base 4, 403 in base 6, and 103 in base 12 (and 93 in base 16, 83 in base 18, and 63 in base 24).

The binary form of 147 (10010011) contains all two-digit binary numbers (00, 01, 10, and 11) in a sequence.

The digits forming 147 also form the left-hand column of a normal decimal keypad.

Source: What's Special About This Number?