866563 has 4 divisors (see below), whose sum is σ = 871920. Its totient is φ = 861208.

The previous prime is 866519. The next prime is 866573. The reversal of 866563 is 365668.

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 866563 - 2⁹ = 866051 is a prime.

It is a Duffinian number.

It is a plaindrome in base 13.

It is not an unprimeable number, because it can be changed into a prime (866513) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2428 + ... + 2761.

It is an arithmetic number, because the mean of its divisors is an integer number (217980).

2⁸⁶⁶⁵⁶³ is an apocalyptic number.

866563 is a deficient number, since it is larger than the sum of its proper divisors (5357).

866563 is a wasteful number, since it uses less digits than its factorization.

866563 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5356.

The product of its digits is 25920, while the sum is 34.

The square root of 866563 is about 930.8936566547. The cubic root of 866563 is about 95.3381485932.

The spelling of 866563 in words is "eight hundred sixty-six thousand, five hundred sixty-three".