816863 has 4 divisors (see below), whose sum is σ = 819000. Its totient is φ = 814728.

The previous prime is 816859. The next prime is 816869. The reversal of 816863 is 368618.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 368618 = 2 ⋅184309.

It is a cyclic number.

It is not a de Polignac number, because 816863 - 2² = 816859 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (816869) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 320 + ... + 1317.

It is an arithmetic number, because the mean of its divisors is an integer number (204750).

2⁸¹⁶⁸⁶³ is an apocalyptic number.

816863 is a deficient number, since it is larger than the sum of its proper divisors (2137).

816863 is a wasteful number, since it uses less digits than its factorization.

816863 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2136.

The product of its digits is 6912, while the sum is 32.

The square root of 816863 is about 903.8047355486. The cubic root of 816863 is about 93.4795059318.

The spelling of 816863 in words is "eight hundred sixteen thousand, eight hundred sixty-three".