6639191200 has 144 divisors (see below), whose sum is σ = 16923463704. Its totient is φ = 2540851200.

The previous prime is 6639191179. The next prime is 6639191231. The reversal of 6639191200 is 21919366.

It can be written as a sum of positive squares in 12 ways, for example, as 721889424 + 5917301776 = 26868^2 + 76924^2 .

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a self number, because there is not a number n which added to its sum of digits gives 6639191200.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1803762 + ... + 1807438.

It is the magic constant of a 2368 × 2368 magic square.

Almost surely, 2^6639191200 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 6639191200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8461731852).

6639191200 is an abundant number, since it is smaller than the sum of its proper divisors (10284272504).

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

6639191200 is a wasteful number, since it uses less digits than its factorization.

6639191200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3795 (or 3782 counting only the distinct ones).

The product of its (nonzero) digits is 17496, while the sum is 37.

The square root of 6639191200 is about 81481.2321949049. The cubic root of 6639191200 is about 1879.4829572562.

The spelling of 6639191200 in words is "six billion, six hundred thirty-nine million, one hundred ninety-one thousand, two hundred".