816805 has 8 divisors (see below), whose sum is σ = 1069344. Its totient is φ = 594000.

The previous prime is 816779. The next prime is 816811. The reversal of 816805 is 508618.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 816805 - 2¹⁷ = 685733 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable 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 7 ways as a sum of consecutive naturals, for example, 7371 + ... + 7480.

It is an arithmetic number, because the mean of its divisors is an integer number (133668).

2⁸¹⁶⁸⁰⁵ is an apocalyptic number.

It is an amenable number.

816805 is a deficient number, since it is larger than the sum of its proper divisors (252539).

816805 is a wasteful number, since it uses less digits than its factorization.

816805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14867.

The product of its (nonzero) digits is 1920, while the sum is 28.

The square root of 816805 is about 903.7726484022. The cubic root of 816805 is about 93.4772934271.

It can be divided in two parts, 81 and 6805, that added together give a palindrome (6886).

The spelling of 816805 in words is "eight hundred sixteen thousand, eight hundred five".