8447191820 has 24 divisors (see below), whose sum is σ = 17773172928. Its totient is φ = 3372387200.

The previous prime is 8447191799. The next prime is 8447191847. The reversal of 8447191820 is 281917448.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 394916 + ... + 415755.

It is an arithmetic number, because the mean of its divisors is an integer number (740548872).

Almost surely, 2^8447191820 is an apocalyptic number.

It is an amenable number.

8447191820 is an abundant number, since it is smaller than the sum of its proper divisors (9325981108).

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

8447191820 is a wasteful number, since it uses less digits than its factorization.

8447191820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 811201 (or 811199 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 44.

The square root of 8447191820 is about 91908.6057994571. The cubic root of 8447191820 is about 2036.5924000171.

The spelling of 8447191820 in words is "eight billion, four hundred forty-seven million, one hundred ninety-one thousand, eight hundred twenty".