866623 has 2 divisors, whose sum is σ = 866624. Its totient is φ = 866622.

The previous prime is 866581. The next prime is 866629. The reversal of 866623 is 326668.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-866623 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (866629) 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 as a sum of consecutive naturals, namely, 433311 + 433312.

It is an arithmetic number, because the mean of its divisors is an integer number (433312).

2⁸⁶⁶⁶²³ is an apocalyptic number.

866623 is a deficient number, since it is larger than the sum of its proper divisors (1).

866623 is an equidigital number, since it uses as much as digits as its factorization.

866623 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10368, while the sum is 31.

The square root of 866623 is about 930.9258831937. The cubic root of 866623 is about 95.3403489167.

The spelling of 866623 in words is "eight hundred sixty-six thousand, six hundred twenty-three".