8640821291 has 4 divisors (see below), whose sum is σ = 8641202592. Its totient is φ = 8640439992.

The previous prime is 8640821281. The next prime is 8640821317. The reversal of 8640821291 is 1921280468.

8640821291 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 8640821291 - 2¹⁰ = 8640820267 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8640821281) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 154355 + ... + 202748.

It is an arithmetic number, because the mean of its divisors is an integer number (2160300648).

Almost surely, 2^8640821291 is an apocalyptic number.

8640821291 is a deficient number, since it is larger than the sum of its proper divisors (381301).

8640821291 is a wasteful number, since it uses less digits than its factorization.

8640821291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 381300.

The product of its (nonzero) digits is 55296, while the sum is 41.

The square root of 8640821291 is about 92956.0180461706. The cubic root of 8640821291 is about 2052.0361519083.

The spelling of 8640821291 in words is "eight billion, six hundred forty million, eight hundred twenty-one thousand, two hundred ninety-one".