816309 has 12 divisors (see below), whose sum is σ = 1269996. Its totient is φ = 502272.

The previous prime is 816271. The next prime is 816317. The reversal of 816309 is 903618.

It can be written as a sum of positive squares in 2 ways, for example, as 140625 + 675684 = 375^2 + 822^2 .

It is not a de Polignac number, because 816309 - 2¹² = 812213 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Curzon number.

It is a plaindrome in base 12.

It is a zygodrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (816329) by changing a digit.

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, 3372 + ... + 3605.

It is an arithmetic number, because the mean of its divisors is an integer number (105833).

2⁸¹⁶³⁰⁹ is an apocalyptic number.

It is an amenable number.

816309 is a deficient number, since it is larger than the sum of its proper divisors (453687).

816309 is a wasteful number, since it uses less digits than its factorization.

816309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6996 (or 6993 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 816309 is about 903.4982014371. The cubic root of 816309 is about 93.4583684182.

The spelling of 816309 in words is "eight hundred sixteen thousand, three hundred nine".