6646669680 has 480 divisors, whose sum is σ = 25526223360. Its totient is φ = 1422489600.

The previous prime is 6646669649. The next prime is 6646669723. The reversal of 6646669680 is 869666466.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is a self number, because there is not a number n which added to its sum of digits gives 6646669680.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 33739342 + ... + 33739538.

It is an arithmetic number, because the mean of its divisors is an integer number (53179632).

Almost surely, 2^6646669680 is an apocalyptic number.

6646669680 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 6646669680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12763111680).

6646669680 is an abundant number, since it is smaller than the sum of its proper divisors (18879553680).

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

6646669680 is a wasteful number, since it uses less digits than its factorization.

6646669680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 397 (or 384 counting only the distinct ones).

The product of its (nonzero) digits is 13436928, while the sum is 57.

The square root of 6646669680 is about 81527.1100922877. The cubic root of 6646669680 is about 1880.1883846232.

The spelling of 6646669680 in words is "six billion, six hundred forty-six million, six hundred sixty-nine thousand, six hundred eighty".