866819 has 2 divisors, whose sum is σ = 866820. Its totient is φ = 866818.

The previous prime is 866783. The next prime is 866843. The reversal of 866819 is 918668.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-866819 is a prime.

It is a super-2 number, since 2×866819² = 1502750357522, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 866819.

It is not a weakly prime, because it can be changed into another prime (866849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 433409 + 433410.

It is an arithmetic number, because the mean of its divisors is an integer number (433410).

2⁸⁶⁶⁸¹⁹ is an apocalyptic number.

866819 is a deficient number, since it is larger than the sum of its proper divisors (1).

866819 is an equidigital number, since it uses as much as digits as its factorization.

866819 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20736, while the sum is 38.

The square root of 866819 is about 931.0311487807. The cubic root of 866819 is about 95.3475359326.

The spelling of 866819 in words is "eight hundred sixty-six thousand, eight hundred nineteen".