816813 has 12 divisors (see below), whose sum is σ = 1205568. Its totient is φ = 532680.

The previous prime is 816811. The next prime is 816817. The reversal of 816813 is 318618.

It is not a de Polignac number, because 816813 - 2¹ = 816811 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (816811) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 543 + ... + 1388.

It is an arithmetic number, because the mean of its divisors is an integer number (100464).

2⁸¹⁶⁸¹³ is an apocalyptic number.

It is an amenable number.

816813 is a deficient number, since it is larger than the sum of its proper divisors (388755).

816813 is a wasteful number, since it uses less digits than its factorization.

816813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1984 (or 1981 counting only the distinct ones).

The product of its digits is 1152, while the sum is 27.

The square root of 816813 is about 903.7770742833. Note that the first 3 decimals coincide. The cubic root of 816813 is about 93.4775986064.

The spelling of 816813 in words is "eight hundred sixteen thousand, eight hundred thirteen".