8666543221 has 12 divisors (see below), whose sum is σ = 10519816032. Its totient is φ = 7105487928.

The previous prime is 8666543191. The next prime is 8666543257. The reversal of 8666543221 is 1223456668.

It is not a de Polignac number, because 8666543221 - 2²³ = 8658154613 is a prime.

It is a super-3 number, since 3×8666543221³ (a number of 31 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8666546221) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3843835 + ... + 3846088.

It is an arithmetic number, because the mean of its divisors is an integer number (876651336).

Almost surely, 2^8666543221 is an apocalyptic number.

It is an amenable number.

8666543221 is a deficient number, since it is larger than the sum of its proper divisors (1853272811).

8666543221 is a wasteful number, since it uses less digits than its factorization.

8666543221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7689960 (or 7689953 counting only the distinct ones).

The product of its digits is 414720, while the sum is 43.

The square root of 8666543221 is about 93094.2706131801. The cubic root of 8666543221 is about 2054.0702966156.

Adding to 8666543221 its reverse (1223456668), we get a palindrome (9889999889).

The spelling of 8666543221 in words is "eight billion, six hundred sixty-six million, five hundred forty-three thousand, two hundred twenty-one".