866543 has 4 divisors (see below), whose sum is σ = 894528. Its totient is φ = 838560.

The previous prime is 866519. The next prime is 866573. The reversal of 866543 is 345668.

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

It is a cyclic number.

It is not a de Polignac number, because 866543 - 2¹² = 862447 is a prime.

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 (866513) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13946 + ... + 14007.

It is an arithmetic number, because the mean of its divisors is an integer number (223632).

2⁸⁶⁶⁵⁴³ is an apocalyptic number.

866543 is a deficient number, since it is larger than the sum of its proper divisors (27985).

866543 is a wasteful number, since it uses less digits than its factorization.

866543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27984.

The product of its digits is 17280, while the sum is 32.

The square root of 866543 is about 930.8829142271. The cubic root of 866543 is about 95.3374151294.

The spelling of 866543 in words is "eight hundred sixty-six thousand, five hundred forty-three".