8643756221 has 8 divisors (see below), whose sum is σ = 8878545720. Its totient is φ = 8409028608.

The previous prime is 8643756197. The next prime is 8643756227. The reversal of 8643756221 is 1226573468.

It can be written as a sum of positive squares in 4 ways, for example, as 4288416196 + 4355340025 = 65486^2 + 65995^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 8643756221 - 2¹⁸ = 8643494077 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8643756227) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 478685 + ... + 496413.

It is an arithmetic number, because the mean of its divisors is an integer number (1109818215).

Almost surely, 2^8643756221 is an apocalyptic number.

It is an amenable number.

8643756221 is a deficient number, since it is larger than the sum of its proper divisors (234789499).

8643756221 is a wasteful number, since it uses less digits than its factorization.

8643756221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30943.

The product of its digits is 483840, while the sum is 44.

The square root of 8643756221 is about 92971.8033653215. The cubic root of 8643756221 is about 2052.2684562427.

The spelling of 8643756221 in words is "eight billion, six hundred forty-three million, seven hundred fifty-six thousand, two hundred twenty-one".