6728721537 has 4 divisors (see below), whose sum is σ = 8971628720. Its totient is φ = 4485814356.

The previous prime is 6728721521. The next prime is 6728721577. The reversal of 6728721537 is 7351278276.

6728721537 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

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.

It is not a de Polignac number, because 6728721537 - 2⁴ = 6728721521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6728721577) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1121453587 + ... + 1121453592.

It is an arithmetic number, because the mean of its divisors is an integer number (2242907180).

Almost surely, 2^6728721537 is an apocalyptic number.

It is an amenable number.

6728721537 is a deficient number, since it is larger than the sum of its proper divisors (2242907183).

6728721537 is a wasteful number, since it uses less digits than its factorization.

6728721537 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2242907182.

The product of its digits is 987840, while the sum is 48.

The square root of 6728721537 is about 82028.7848075296. The cubic root of 6728721537 is about 1887.8936190157.

The spelling of 6728721537 in words is "six billion, seven hundred twenty-eight million, seven hundred twenty-one thousand, five hundred thirty-seven".