39 (number)

39 is the natural number following 38 and preceding 40.

List of numbers — Integers << 30 31 32 33 34 35 36 37 38 39 >>
Cardinal	thirty-nine
Ordinal	39th (thirty-ninth)
Factorization	<math>3\cdot 13<math>
Roman numeral	XXXIX
Binary	100111
Hexadecimal	27

In mathematics

Thirty-nine is the sum of five consecutive primes (3 + 5 + 7 + 11 + 13) and the sum of the first three powers of 3 (<math>3^1 + 3^2 + 3^3<math>). Given 39, the Mertens function returns 0.

In other fields

Thirty-nine is also:

• The atomic number of yttrium.
• In the title of the John Buchan, novel The Thirty-Nine Steps.
• The code for international direct-dialed phone calls to Italy.
• I-39 is the designation for a US interstate highway from Normal, Illinois to Wausau, Wisconsin.
• The eternal age of comedian Jack Benny, and many other people as they grow older.
• The year A.D. 39, 39 BC, or 1939.
• Japanese Internet chat slang for "thank you" when written with numbers.