8643781220 has 24 divisors (see below), whose sum is σ = 18422867904. Its totient is φ = 3405907296.

The previous prime is 8643781213. The next prime is 8643781229. The reversal of 8643781220 is 221873468.

It is not an unprimeable number, because it can be changed into a prime (8643781229) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 3223952 + ... + 3226631.

It is an arithmetic number, because the mean of its divisors is an integer number (767619496).

Almost surely, 2^8643781220 is an apocalyptic number.

It is an amenable number.

8643781220 is an abundant number, since it is smaller than the sum of its proper divisors (9779086684).

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

8643781220 is a wasteful number, since it uses less digits than its factorization.

8643781220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6450659 (or 6450657 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 41.

The square root of 8643781220 is about 92971.9378092121. The cubic root of 8643781220 is about 2052.2704347271.

The spelling of 8643781220 in words is "eight billion, six hundred forty-three million, seven hundred eighty-one thousand, two hundred twenty".