129856 has 14 divisors (see below), whose sum is σ = 257810. Its totient is φ = 64896.

The previous prime is 129853. The next prime is 129887. The reversal of 129856 is 658921.

It can be written as a sum of positive squares in only one way, i.e., 129600 + 256 = 360^2 + 16^2 .

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (129853) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 951 + ... + 1078.

It is an arithmetic number, because the mean of its divisors is an integer number (18415).

2¹²⁹⁸⁵⁶ is an apocalyptic number.

129856 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

129856 is a deficient number, since it is larger than the sum of its proper divisors (127954).

129856 is an equidigital number, since it uses as much as digits as its factorization.

129856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2041 (or 2031 counting only the distinct ones).

The product of its digits is 4320, while the sum is 31.

The square root of 129856 is about 360.3553801458. The cubic root of 129856 is about 50.6392587992.

The spelling of 129856 in words is "one hundred twenty-nine thousand, eight hundred fifty-six".