6728729 has 6 divisors (see below), whose sum is σ = 7827354. Its totient is φ = 5767440.

The previous prime is 6728723. The next prime is 6728731. The reversal of 6728729 is 9278276.

6728729 = 212² + 213² + ... + 309².

It can be written as a sum of positive squares in only one way, i.e., 6528025 + 200704 = 2555^2 + 448^2 .

It is not a de Polignac number, because 6728729 - 2⁴ = 6728713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6728723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 68612 + ... + 68709.

It is an arithmetic number, because the mean of its divisors is an integer number (1304559).

Almost surely, 2^6728729 is an apocalyptic number.

It is an amenable number.

6728729 is a deficient number, since it is larger than the sum of its proper divisors (1098625).

6728729 is a wasteful number, since it uses less digits than its factorization.

6728729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137335 (or 137328 counting only the distinct ones).

The product of its digits is 84672, while the sum is 41.

The square root of 6728729 is about 2593.9793753999. The cubic root of 6728729 is about 188.7894316986.

The spelling of 6728729 in words is "six million, seven hundred twenty-eight thousand, seven hundred twenty-nine".