129085905 has 32 divisors (see below), whose sum is σ = 234138240. Its totient is φ = 60203520.

The previous prime is 129085849. The next prime is 129085907. The reversal of 129085905 is 509580921.

It is not a de Polignac number, because 129085905 - 2⁶ = 129085841 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (129085907) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 13716 + ... + 21125.

It is an arithmetic number, because the mean of its divisors is an integer number (7316820).

Almost surely, 2^129085905 is an apocalyptic number.

129085905 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

129085905 is a deficient number, since it is larger than the sum of its proper divisors (105052335).

129085905 is a wasteful number, since it uses less digits than its factorization.

129085905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34881.

The product of its (nonzero) digits is 32400, while the sum is 39.

The square root of 129085905 is about 11361.5978189689. The cubic root of 129085905 is about 505.3895696731.

The spelling of 129085905 in words is "one hundred twenty-nine million, eighty-five thousand, nine hundred five".