8521971720 has 64 divisors (see below), whose sum is σ = 26256899520. Its totient is φ = 2211105024.

The previous prime is 8521971719. The next prime is 8521971793. The reversal of 8521971720 is 271791258.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 955242 + ... + 964121.

It is an arithmetic number, because the mean of its divisors is an integer number (410264055).

Almost surely, 2^8521971720 is an apocalyptic number.

It is an amenable number.

8521971720 is an abundant number, since it is smaller than the sum of its proper divisors (17734927800).

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

8521971720 is a wasteful number, since it uses less digits than its factorization.

8521971720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1919414 (or 1919410 counting only the distinct ones).

The product of its (nonzero) digits is 70560, while the sum is 42.

The square root of 8521971720 is about 92314.5260508876. The cubic root of 8521971720 is about 2042.5844886340.

The spelling of 8521971720 in words is "eight billion, five hundred twenty-one million, nine hundred seventy-one thousand, seven hundred twenty".