6647582781 has 24 divisors (see below), whose sum is σ = 10997847744. Its totient is φ = 3790290240.

The previous prime is 6647582759. The next prime is 6647582789. The reversal of 6647582781 is 1872857466.

6647582781 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 6647582781 - 2⁷ = 6647582653 is a prime.

It is a super-2 number, since 2×6647582781² = 88380713660495387922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6647582789) 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, 86655 + ... + 144236.

It is an arithmetic number, because the mean of its divisors is an integer number (458243656).

Almost surely, 2^6647582781 is an apocalyptic number.

It is an amenable number.

6647582781 is a deficient number, since it is larger than the sum of its proper divisors (4350264963).

6647582781 is a wasteful number, since it uses less digits than its factorization.

6647582781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 231361 (or 231358 counting only the distinct ones).

The product of its digits is 4515840, while the sum is 54.

The square root of 6647582781 is about 81532.7098838252. The cubic root of 6647582781 is about 1880.2744790317.

The spelling of 6647582781 in words is "six billion, six hundred forty-seven million, five hundred eighty-two thousand, seven hundred eighty-one".