6561660 has 96 divisors (see below), whose sum is σ = 22256640. Its totient is φ = 1410048.

The previous prime is 6561649. The next prime is 6561673. The reversal of 6561660 is 661656.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6681 + ... + 7599.

It is an arithmetic number, because the mean of its divisors is an integer number (231840).

Almost surely, 2^6561660 is an apocalyptic number.

6561660 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 6561660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11128320).

6561660 is an abundant number, since it is smaller than the sum of its proper divisors (15694980).

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

6561660 is a wasteful number, since it uses less digits than its factorization.

6561660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 955 (or 953 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 30.

The square root of 6561660 is about 2561.5737350309. The cubic root of 6561660 is about 187.2138212091.

The spelling of 6561660 in words is "six million, five hundred sixty-one thousand, six hundred sixty".