821085 has 32 divisors (see below), whose sum is σ = 1436160. Its totient is φ = 399168.

The previous prime is 821081. The next prime is 821089. The reversal of 821085 is 580128.

821085 = 76² + 77² + ... + 142².

It is an interprime number because it is at equal distance from previous prime (821081) and next prime (821089).

It is not a de Polignac number, because 821085 - 2² = 821081 is a prime.

821085 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821081) 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 31 ways as a sum of consecutive naturals, for example, 12222 + ... + 12288.

It is an arithmetic number, because the mean of its divisors is an integer number (44880).

2⁸²¹⁰⁸⁵ is an apocalyptic number.

It is an amenable number.

821085 is a deficient number, since it is larger than the sum of its proper divisors (615075).

821085 is a wasteful number, since it uses less digits than its factorization.

821085 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137.

The product of its (nonzero) digits is 640, while the sum is 24.

The square root of 821085 is about 906.1374067988. The cubic root of 821085 is about 93.6402805298.

The spelling of 821085 in words is "eight hundred twenty-one thousand, eighty-five".