816389 has 6 divisors (see below), whose sum is σ = 949734. Its totient is φ = 699720.

The previous prime is 816377. The next prime is 816401. The reversal of 816389 is 983618.

It is an interprime number because it is at equal distance from previous prime (816377) and next prime (816401).

It can be written as a sum of positive squares in only one way, i.e., 693889 + 122500 = 833^2 + 350^2 .

It is not a de Polignac number, because 816389 - 2⁸ = 816133 is a prime.

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

It is a Duffinian number.

It is a Curzon number.

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 816389.

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

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8282 + ... + 8379.

It is an arithmetic number, because the mean of its divisors is an integer number (158289).

2⁸¹⁶³⁸⁹ is an apocalyptic number.

It is an amenable number.

816389 is a deficient number, since it is larger than the sum of its proper divisors (133345).

816389 is a wasteful number, since it uses less digits than its factorization.

816389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16675 (or 16668 counting only the distinct ones).

The product of its digits is 10368, while the sum is 35.

The square root of 816389 is about 903.5424727150. The cubic root of 816389 is about 93.4614213574.

The spelling of 816389 in words is "eight hundred sixteen thousand, three hundred eighty-nine".