6921631872 has 128 divisors (see below), whose sum is σ = 21630283200. Its totient is φ = 2171473920.

The previous prime is 6921631859. The next prime is 6921631897. The reversal of 6921631872 is 2781361296.

6921631872 is a `hidden beast` number, since 6 + 9 + 2 + 1 + 631 + 8 + 7 + 2 = 666.

It is a tau number, because it is divible by the number of its divisors (128).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 154 + ... + 117657.

Almost surely, 2^6921631872 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 6921631872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10815141600).

6921631872 is an abundant number, since it is smaller than the sum of its proper divisors (14708651328).

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

6921631872 is a wasteful number, since it uses less digits than its factorization.

6921631872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 117851 (or 117833 counting only the distinct ones).

The product of its digits is 217728, while the sum is 45.

The square root of 6921631872 is about 83196.3453043462. The cubic root of 6921631872 is about 1905.7656690284.

The spelling of 6921631872 in words is "six billion, nine hundred twenty-one million, six hundred thirty-one thousand, eight hundred seventy-two".