666688543 has 8 divisors (see below), whose sum is σ = 674319600. Its totient is φ = 659101248.

The previous prime is 666688513. The next prime is 666688559. The reversal of 666688543 is 345886666.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-666688543 is a prime.

It is a super-2 number, since 2×666688543² = 888947226734925698, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666688513) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20203 + ... + 41731.

It is an arithmetic number, because the mean of its divisors is an integer number (84289950).

Almost surely, 2^666688543 is an apocalyptic number.

666688543 is a deficient number, since it is larger than the sum of its proper divisors (7631057).

666688543 is a wasteful number, since it uses less digits than its factorization.

666688543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21881.

The product of its digits is 4976640, while the sum is 52.

The square root of 666688543 is about 25820.3126046142. The cubic root of 666688543 is about 873.5900200005.

The spelling of 666688543 in words is "six hundred sixty-six million, six hundred eighty-eight thousand, five hundred forty-three".