816585 has 48 divisors (see below), whose sum is σ = 1674432. Its totient is φ = 336000.

The previous prime is 816581. The next prime is 816587. The reversal of 816585 is 585618.

It is not a de Polignac number, because 816585 - 2² = 816581 is a prime.

It is a super-2 number, since 2×816585² = 1333622124450, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is an Ulam number.

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

It is a Curzon number.

816585 is a lucky number.

It is a plaindrome in base 12.

It is not an unprimeable number, because it can be changed into a prime (816581) 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 47 ways as a sum of consecutive naturals, for example, 8035 + ... + 8135.

It is an arithmetic number, because the mean of its divisors is an integer number (34884).

2⁸¹⁶⁵⁸⁵ is an apocalyptic number.

It is an amenable number.

816585 is an abundant number, since it is smaller than the sum of its proper divisors (857847).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

816585 is a wasteful number, since it uses less digits than its factorization.

816585 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134 (or 127 counting only the distinct ones).

The product of its digits is 9600, while the sum is 33.

The square root of 816585 is about 903.6509281797. The cubic root of 816585 is about 93.4689002157.

Adding to 816585 its sum of digits (33), we get a palindrome (816618).

It can be divided in two parts, 81 and 6585, that added together give a palindrome (6666).

The spelling of 816585 in words is "eight hundred sixteen thousand, five hundred eighty-five".