6721728 has 56 divisors (see below), whose sum is σ = 19159728. Its totient is φ = 2067456.

The previous prime is 6721723. The next prime is 6721733. The reversal of 6721728 is 8271276.

It is an interprime number because it is at equal distance from previous prime (6721723) and next prime (6721733).

It is not an unprimeable number, because it can be changed into a prime (6721723) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1150 + ... + 3842.

It is an arithmetic number, because the mean of its divisors is an integer number (342138).

Almost surely, 2^6721728 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6721728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9579864).

6721728 is an abundant number, since it is smaller than the sum of its proper divisors (12438000).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6721728 is a wasteful number, since it uses less digits than its factorization.

6721728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2721 (or 2711 counting only the distinct ones).

The product of its digits is 9408, while the sum is 33.

The square root of 6721728 is about 2592.6295531757. The cubic root of 6721728 is about 188.7239327772.

The spelling of 6721728 in words is "six million, seven hundred twenty-one thousand, seven hundred twenty-eight".