6728561 has 16 divisors (see below), whose sum is σ = 8018304. Its totient is φ = 5526144.

The previous prime is 6728543. The next prime is 6728563. The reversal of 6728561 is 1658276.

It is a cyclic number.

It is not a de Polignac number, because 6728561 - 2¹⁸ = 6466417 is a prime.

It is a Smith number, since the sum of its digits (35) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (6728563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21341 + ... + 21653.

It is an arithmetic number, because the mean of its divisors is an integer number (501144).

Almost surely, 2^6728561 is an apocalyptic number.

It is an amenable number.

6728561 is a deficient number, since it is larger than the sum of its proper divisors (1289743).

6728561 is a wasteful number, since it uses less digits than its factorization.

6728561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 440.

The product of its digits is 20160, while the sum is 35.

The square root of 6728561 is about 2593.9469925193. The cubic root of 6728561 is about 188.7878604812.

The spelling of 6728561 in words is "six million, seven hundred twenty-eight thousand, five hundred sixty-one".