129

129 = 3 x 43.

129 is 10000001 in base (binary). It is 333 in base 6.

129 is the smallest number with four representations as a sum of three positive squares: 129 = 1² + 8² + 8² = 2² + 2² + 11² = 2² + 5² + 10² = 4² + 7² + 8².

129 is the sum of the first ten primes: 129 = 2 + 3 + 5 + 7 + 11 + 13 + 17 + 19 + 23 + 29.

129 is the smallest sum of distinct seventh powers: 129 = 1⁷ + 2⁷.

Source: Number Gossip