866399 has 2 divisors, whose sum is σ = 866400. Its totient is φ = 866398.

The previous prime is 866389. The next prime is 866417. The reversal of 866399 is 993668.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-866399 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 866399.

It is not a weakly prime, because it can be changed into another prime (866309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 433199 + 433200.

It is an arithmetic number, because the mean of its divisors is an integer number (433200).

2⁸⁶⁶³⁹⁹ is an apocalyptic number.

866399 is a deficient number, since it is larger than the sum of its proper divisors (1).

866399 is an equidigital number, since it uses as much as digits as its factorization.

866399 is an evil number, because the sum of its binary digits is even.

The product of its digits is 69984, while the sum is 41.

The square root of 866399 is about 930.8055650886. The cubic root of 866399 is about 95.3321338573.

The spelling of 866399 in words is "eight hundred sixty-six thousand, three hundred ninety-nine".