6561728 has 56 divisors (see below), whose sum is σ = 14246352. Its totient is φ = 2985984.

The previous prime is 6561721. The next prime is 6561761. The reversal of 6561728 is 8271656.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6561721) 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, 40175 + ... + 40337.

Almost surely, 2^6561728 is an apocalyptic number.

6561728 is a gapful number since it is divisible by the number (68) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6561728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7123176).

6561728 is an abundant number, since it is smaller than the sum of its proper divisors (7684624).

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

6561728 is a wasteful number, since it uses less digits than its factorization.

6561728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 229 (or 219 counting only the distinct ones).

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

The square root of 6561728 is about 2561.5870080870. The cubic root of 6561728 is about 187.2144679202.

The spelling of 6561728 in words is "six million, five hundred sixty-one thousand, seven hundred twenty-eight".