6689447856 has 720 divisors, whose sum is σ = 25321025184. Its totient is φ = 1693052928.

The previous prime is 6689447837. The next prime is 6689447867. The reversal of 6689447856 is 6587449866.

6689447856 is a `hidden beast` number, since 66 + 89 + 447 + 8 + 56 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

Its product of digits (69672960) is a multiple of the sum of its prime divisors (135).

It is a junction number, because it is equal to n+sod(n) for n = 6689447793 and 6689447802.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 91636236 + ... + 91636308.

Almost surely, 2^6689447856 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 6689447856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12660512592).

6689447856 is an abundant number, since it is smaller than the sum of its proper divisors (18631577328).

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

6689447856 is a wasteful number, since it uses less digits than its factorization.

6689447856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160 (or 135 counting only the distinct ones).

The product of its digits is 69672960, while the sum is 63.

The square root of 6689447856 is about 81789.0448409810. The cubic root of 6689447856 is about 1884.2134124751.

The spelling of 6689447856 in words is "six billion, six hundred eighty-nine million, four hundred forty-seven thousand, eight hundred fifty-six".