729409 has 4 divisors (see below), whose sum is σ = 746416. Its totient is φ = 712404.

The previous prime is 729403. The next prime is 729413. The reversal of 729409 is 904927.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 904927 = 17 ⋅53231.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-729409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (729403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8439 + ... + 8524.

It is an arithmetic number, because the mean of its divisors is an integer number (186604).

2⁷²⁹⁴⁰⁹ is an apocalyptic number.

It is an amenable number.

729409 is a deficient number, since it is larger than the sum of its proper divisors (17007).

729409 is a wasteful number, since it uses less digits than its factorization.

729409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17006.

The product of its (nonzero) digits is 4536, while the sum is 31.

The square root of 729409 is about 854.0544479130. The cubic root of 729409 is about 90.0168281290.

The spelling of 729409 in words is "seven hundred twenty-nine thousand, four hundred nine".