6728521 has 2 divisors, whose sum is σ = 6728522. Its totient is φ = 6728520.

The previous prime is 6728503. The next prime is 6728531. The reversal of 6728521 is 1258276.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6702921 + 25600 = 2589^2 + 160^2 .

It is a cyclic number.

It is not a de Polignac number, because 6728521 - 2⁹ = 6728009 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (6728531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3364260 + 3364261.

It is an arithmetic number, because the mean of its divisors is an integer number (3364261).

Almost surely, 2^6728521 is an apocalyptic number.

It is an amenable number.

6728521 is a deficient number, since it is larger than the sum of its proper divisors (1).

6728521 is an equidigital number, since it uses as much as digits as its factorization.

6728521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6720, while the sum is 31.

The square root of 6728521 is about 2593.9392822501. The cubic root of 6728521 is about 188.7874863780.

The spelling of 6728521 in words is "six million, seven hundred twenty-eight thousand, five hundred twenty-one".