6581771856 has 160 divisors (see below), whose sum is σ = 20705341440. Its totient is φ = 1985212800.

The previous prime is 6581771849. The next prime is 6581771857.

6581771856 is a `hidden beast` number, since 6 + 581 + 7 + 7 + 1 + 8 + 56 = 666.

6581771856 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6581771857) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1056591 + ... + 1062801.

It is an arithmetic number, because the mean of its divisors is an integer number (129408384).

Almost surely, 2^6581771856 is an apocalyptic number.

6581771856 is a gapful number since it is divisible by the number (66) 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 6581771856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10352670720).

6581771856 is an abundant number, since it is smaller than the sum of its proper divisors (14123569584).

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

6581771856 is a wasteful number, since it uses less digits than its factorization.

6581771856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6462 (or 6450 counting only the distinct ones).

The product of its digits is 2822400, while the sum is 54.

The square root of 6581771856 is about 81128.1200078000. The cubic root of 6581771856 is about 1874.0489974117.

The spelling of 6581771856 in words is "six billion, five hundred eighty-one million, seven hundred seventy-one thousand, eight hundred fifty-six".