129709321 has 9 divisors (see below), whose sum is σ = 150979149. Its totient is φ = 111111084.

The previous prime is 129709313. The next prime is 129709357. The reversal of 129709321 is 123907921.

It is a happy number.

The square root of 129709321 is 11389.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 129709321 - 2³ = 129709313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (129709381) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 78910 + ... + 80536.

It is an arithmetic number, because the mean of its divisors is an integer number (16775461).

Almost surely, 2^129709321 is an apocalyptic number.

129709321 is the 11389-th square number.

129709321 is the 5695-th centered octagonal number.

It is an amenable number.

129709321 is a deficient number, since it is larger than the sum of its proper divisors (21269828).

129709321 is an frugal number, since it uses more digits than its factorization.

129709321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3268 (or 1634 counting only the distinct ones).

The product of its (nonzero) digits is 6804, while the sum is 34.

The cubic root of 129709321 is about 506.2018507070.

The spelling of 129709321 in words is "one hundred twenty-nine million, seven hundred nine thousand, three hundred twenty-one".