866538 has 24 divisors (see below), whose sum is σ = 1948128. Its totient is φ = 288684.

The previous prime is 866519. The next prime is 866573. The reversal of 866538 is 835668.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is a plaindrome in base 13.

It is an unprimeable number.

866538 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 406 + ... + 1377.

It is an arithmetic number, because the mean of its divisors is an integer number (81172).

2⁸⁶⁶⁵³⁸ is an apocalyptic number.

866538 is an abundant number, since it is smaller than the sum of its proper divisors (1081590).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

866538 is a wasteful number, since it uses less digits than its factorization.

866538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1800 (or 1788 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 866538 is about 930.8802286009. The cubic root of 866538 is about 95.3372317617.

The spelling of 866538 in words is "eight hundred sixty-six thousand, five hundred thirty-eight".