29 (number)

The number 29 is the natural number following 28 and preceding 30. It is a prime number and a deficient number.

Mathematics:

• 29 is the 10th prime number. The previous prime is 23 and the next is 31.
• 29 is a twin prime with 31, as they differ by 2.
• It is an emirp, meaning that when its digits are reversed (92), the result is a different prime number.
• 29 can be expressed as the sum of three consecutive squares: 2² + 3² + 4² = 4 + 9 + 16 = 29.
• 29 is a Pythagorean prime, meaning it is a prime number of the form 4*n + 1.
• In base 10, 1/29 has a repeating decimal expansion with a period of 28 digits.
• 29 is the magic constant of the 5x5 normal magic square.

Science:

• 29 is the atomic number of copper (Cu).

Other:

• February has 29 days in a leap year.