6581661856 has 96 divisors (see below), whose sum is σ = 16420199040. Its totient is φ = 2522188800.

The previous prime is 6581661851. The next prime is 6581661859.

6581661856 is nontrivially palindromic in base 10.

It is not an unprimeable number, because it can be changed into a prime (6581661851) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 128410 + ... + 172198.

It is an arithmetic number, because the mean of its divisors is an integer number (171043740).

Almost surely, 2^6581661856 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 6581661856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8210099520).

6581661856 is an abundant number, since it is smaller than the sum of its proper divisors (9838537184).

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

6581661856 is a wasteful number, since it uses less digits than its factorization.

6581661856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43878 (or 43870 counting only the distinct ones).

The product of its digits is 2073600, while the sum is 52.

The square root of 6581661856 is about 81127.4420649388. The cubic root of 6581661856 is about 1874.0385571360.

The spelling of 6581661856 in words is "six billion, five hundred eighty-one million, six hundred sixty-one thousand, eight hundred fifty-six".