6661591200 has 864 divisors, whose sum is σ = 27993833280. Its totient is φ = 1515571200.

The previous prime is 6661591087. The next prime is 6661591213. The reversal of 6661591200 is 21951666.

It is a tau number, because it is divible by the number of its divisors (864).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 125690374 + ... + 125690426.

It is an arithmetic number, because the mean of its divisors is an integer number (32400270).

Almost surely, 2^6661591200 is an apocalyptic number.

6661591200 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 6661591200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13996916640).

6661591200 is an abundant number, since it is smaller than the sum of its proper divisors (21332242080).

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

6661591200 is a wasteful number, since it uses less digits than its factorization.

6661591200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139 (or 97 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 36.

The square root of 6661591200 is about 81618.5714160693. The cubic root of 6661591200 is about 1881.5943168040.

The spelling of 6661591200 in words is "six billion, six hundred sixty-one million, five hundred ninety-one thousand, two hundred".