7666543221 has 8 divisors (see below), whose sum is σ = 10222482144. Its totient is φ = 5110816560.

The previous prime is 7666543207. The next prime is 7666543223. The reversal of 7666543221 is 1223456667.

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

It is not a de Polignac number, because 7666543221 - 2³¹ = 5519059573 is a prime.

It is a super-3 number, since 3×7666543221³ (a number of 31 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

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 (7666543223) 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, 76195 + ... + 145391.

It is an arithmetic number, because the mean of its divisors is an integer number (1277810268).

Almost surely, 2^7666543221 is an apocalyptic number.

It is an amenable number.

7666543221 is a deficient number, since it is larger than the sum of its proper divisors (2555938923).

7666543221 is a wasteful number, since it uses less digits than its factorization.

7666543221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106131.

The product of its digits is 362880, while the sum is 42.

The square root of 7666543221 is about 87558.7986498216. The cubic root of 7666543221 is about 1971.8166499799.

Adding to 7666543221 its reverse (1223456667), we get a palindrome (8889999888).

The spelling of 7666543221 in words is "seven billion, six hundred sixty-six million, five hundred forty-three thousand, two hundred twenty-one".