129397729 has 4 divisors (see below), whose sum is σ = 129428740. Its totient is φ = 129366720.

The previous prime is 129397691. The next prime is 129397787. The reversal of 129397729 is 927793921.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 77845329 + 51552400 = 8823^2 + 7180^2 .

It is a cyclic number.

It is not a de Polignac number, because 129397729 - 2¹⁹ = 128873441 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (129397129) 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 3 ways as a sum of consecutive naturals, for example, 8052 + ... + 17989.

It is an arithmetic number, because the mean of its divisors is an integer number (32357185).

Almost surely, 2^129397729 is an apocalyptic number.

It is an amenable number.

129397729 is a deficient number, since it is larger than the sum of its proper divisors (31011).

129397729 is an equidigital number, since it uses as much as digits as its factorization.

129397729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31010.

The product of its digits is 428652, while the sum is 49.

The square root of 129397729 is about 11375.3122594503. The cubic root of 129397729 is about 505.7961874521.

The spelling of 129397729 in words is "one hundred twenty-nine million, three hundred ninety-seven thousand, seven hundred twenty-nine".