666406543 has 4 divisors (see below), whose sum is σ = 726988968. Its totient is φ = 605824120.

The previous prime is 666406537. The next prime is 666406547. The reversal of 666406543 is 345604666.

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

It is not a de Polignac number, because 666406543 - 2⁹ = 666406031 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 666406496 and 666406505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666406547) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30291196 + ... + 30291217.

It is an arithmetic number, because the mean of its divisors is an integer number (181747242).

Almost surely, 2^666406543 is an apocalyptic number.

666406543 is a deficient number, since it is larger than the sum of its proper divisors (60582425).

666406543 is a wasteful number, since it uses less digits than its factorization.

666406543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60582424.

The product of its (nonzero) digits is 311040, while the sum is 40.

The square root of 666406543 is about 25814.8512101077. The cubic root of 666406543 is about 873.4668304787.

The spelling of 666406543 in words is "six hundred sixty-six million, four hundred six thousand, five hundred forty-three".