129729521 has 6 divisors (see below), whose sum is σ = 130239522. Its totient is φ = 129221040.

The previous prime is 129729517. The next prime is 129729539. The reversal of 129729521 is 125927921.

It can be written as a sum of positive squares in only one way, i.e., 99600400 + 30129121 = 9980^2 + 5489^2 .

It is not a de Polignac number, because 129729521 - 2² = 129729517 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (129729421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 248741 + ... + 249261.

It is an arithmetic number, because the mean of its divisors is an integer number (21706587).

Almost surely, 2^129729521 is an apocalyptic number.

It is an amenable number.

129729521 is a deficient number, since it is larger than the sum of its proper divisors (510001).

129729521 is an frugal number, since it uses more digits than its factorization.

129729521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1519 (or 1020 counting only the distinct ones).

The product of its digits is 22680, while the sum is 38.

The square root of 129729521 is about 11389.8867860923. The cubic root of 129729521 is about 506.2281267591.

The spelling of 129729521 in words is "one hundred twenty-nine million, seven hundred twenty-nine thousand, five hundred twenty-one".