6556999680 has 1008 divisors, whose sum is σ = 29807885520. Its totient is φ = 1362493440.

The previous prime is 6556999667. The next prime is 6556999711. The reversal of 6556999680 is 869996556.

6556999680 is a `hidden beast` number, since 6 + 5 + 569 + 9 + 9 + 68 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1008).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 596090875 + ... + 596090885.

It is an arithmetic number, because the mean of its divisors is an integer number (29571315).

Almost surely, 2^6556999680 is an apocalyptic number.

6556999680 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 6556999680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (14903942760).

6556999680 is an abundant number, since it is smaller than the sum of its proper divisors (23250885840).

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

6556999680 is a wasteful number, since it uses less digits than its factorization.

6556999680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76 (or 28 counting only the distinct ones).

The product of its (nonzero) digits is 31492800, while the sum is 63.

The square root of 6556999680 is about 80975.3029015638. The cubic root of 6556999680 is about 1871.6948878144.

The spelling of 6556999680 in words is "six billion, five hundred fifty-six million, nine hundred ninety-nine thousand, six hundred eighty".