6561720 has 96 divisors (see below), whose sum is σ = 23278320. Its totient is φ = 1589760.

The previous prime is 6561719. The next prime is 6561721. The reversal of 6561720 is 271656.

6561720 is a `hidden beast` number, since 656 + 1 + 7 + 2 + 0 = 666.

6561720 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (6561719) and next prime (6561721).

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 23 ways as a sum of consecutive naturals, for example, 3132 + ... + 4788.

Almost surely, 2^6561720 is an apocalyptic number.

6561720 is a gapful number since it is divisible by the number (60) 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 6561720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11639160).

6561720 is an abundant number, since it is smaller than the sum of its proper divisors (16716600).

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

6561720 is a wasteful number, since it uses less digits than its factorization.

6561720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1685 (or 1678 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 27.

The square root of 6561720 is about 2561.5854465545. The cubic root of 6561720 is about 187.2143918368.

Subtracting from 6561720 its reverse (271656), we obtain a square (6290064 = 2508²).

The spelling of 6561720 in words is "six million, five hundred sixty-one thousand, seven hundred twenty".